Term
| What are the main qualities of stem cells? |
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Definition
1) they can give rise to specialized cell types
2) unspecialized
3) prolifirate and replicate many times
4) ability to divide and renew themselves
5) long-term self renewal — daughter cell is unspecialized like parent cell . |
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Term
| Classification of cells according to their potency |
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Definition
Totipotent (All lineages of organism;only the zygote and the first cleavage blastomeres)
Pluripotent (All lineages of body ), Multipotent (Adult stem cells,multiple cell types of one lineage)
Unipotent (cells form one cell type,spermatogonial stem cells). |
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Term
| Which types of cell can embryonic stem cells form? |
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Definition
| Pluripotent = can become any cell present in the human body BUT not trophoectoderm |
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Term
| What is the difference between ESC and ASC? |
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Definition
ESC: stable, can undergo many cell divisions, easy to obtain but blastocyst is destroyed
Adult Stem Cells less stable, capacity for selfrenewal is limited, difficult to isolate in adult tissue |
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Term
| What are KEY PLURIPOTENCY FACTORS? |
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Definition
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Term
| What are the main features of oct4? |
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Definition
Expression in: TE & ICM
Function:it maintains self-renewal and pluripotency by activating its own expression and that of factors such as Sox2 and Nanog
Loss of Oct 4 - inappropriate differentiation (ES cells cannot derived anymore from blastocyste)
Overexpression of Oct4: differentiation into primitive endoderm and mesoderm. |
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Term
| What are the main features of nanog? |
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Definition
Function: required for germline formation.
Loss of nanog in ES : spontaneous differentiation into primitive ectoderm . Loss in other cell types - differentiation into ES .
Overexpression of nanog: promotes self-renewal independent of LIF |
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Term
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Definition
| LEUKEMIA INHIBITOR FACTOR (LIF) and downstream effector STAT3 are essential for maintenance of Pluripotency in mouse ES cells. |
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Term
| How Oct4, Nanog and Sox2 interact? |
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Definition
| OCT4 and SOX2 form a heterodimer that positively regulates the expression of OCT4, Sox2 and Nanog. OCT4, Sox2 and Nanog regulate their own and each other's expression in a highly coordinated manner. |
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Term
| What BMP - family does in stem cells? |
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Definition
- binds to receptor , which then induces phosphorylation of Smad -> gene regulation
- in mouse ES cells can induce expression of an “Inhibitor of differentiation”- factor
- in human ES cells - induces differentiation |
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Term
| What is the STEM CELL NICHES? |
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Definition
| The anatomical location in adult tissues where stem cells reside |
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Term
| Which types of stem cell niche exist? |
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Definition
| Self-renewing niche and quiescent-storage niche |
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Term
| What are characteristics of quiescent-storage niche? |
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Definition
| Resting (G0) stem cells are stored in 'quiescent' niches.Specialized niche cells generate a differentiation- and/or division-repressive environment. Under conditions of stress these might be mobilized to generate mature cells as required, and might then return to empty niches for storage or self-renewal. |
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Term
| What are characteristics of self-renewing niche? |
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Definition
| Quiescent stem cells would be anchored in the centre of the niche, whereas self-renewing stem cells would be located close to the border separating the niche from the non-niche microenvironment (NNM).Niche signals and NNM signals intermingle to form a signalling centre. The appearance of a stem cell at the niche edge would expose it to proliferative signals. |
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Term
| What asymmetry in cell division occurs in self-renewing niche? |
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Definition
| Asymmetric division by environmental asymmetry. |
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Term
| Outline the definitive differentiative decisions |
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Definition
| The first is made at the blastocyst stage, in which the trophectoderm (TE) layer is set aside from the inner cell mass. All three cell lineages — that is, TE, primitive endoderm and epiblast — give rise to distinct stem cell types: trophoblast stem (TS) cells, extraembryonic endoderm stem (XEN) cells and embryonic stem (ES) cells.Immediately after implantation, the epiblast can give rise to a different stem cell population, termed epiblast stem cells (epiSCs). |
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Term
| What is the length of stem cell cell cycle compare to normal cells? |
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Definition
| The cell cycle of embryonic stem (ES) cells is shortened relative to that of most other cells (11–16 hours as opposed to 24 hours):abbreviated G1 phase |
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Term
| Why cell cycle for stem cells is shorter? |
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Definition
| In ES cells, cyclin E–CDK2 (E/2) is constitutively active throughout the cell cycle, which allows the transition of ES cells from M phase directly to late G1. |
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Term
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Definition
| The niche essentially consists of ECM molecules such as collagen, fibronectin, vitronectin and laminin that provide anchorage. Other components include cell adhesion molecules (CAMs) such as E-cadherin, which are responsible for cell–cell adhesion and maintenance of tissue architecture, and growth factors such as leukemia inhibitory factor (LIF) and basic fibroblast growth factor (bFGF). |
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Term
| Types of adult stem cells |
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Definition
| mesenchymal , neuronal, haematopoietic |
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Term
| Where small intestine/colon stem cells reside? |
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Definition
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Term
| Which cell types of stem cell are in small intestine? |
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Definition
| LGR5+ label-retaining cells (LRCs) are Paneth cell precursors that exclusively supply mature Paneth cells. Delta-like 1- expressing (DLL1+) transit-amplifying (TA) cells are secretory cell progenitors supplying goblet cells, endocrine cells and tuft cells.Surviving +4 cell populations function as 'reserve' stem cells to rapidly regenerate the LGR5+ CBC stem cell pool and restore epithelial renewal. |
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Term
| Which cells supply essential factors for small intestine stem cells? |
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Definition
| Both Paneth cells and pericryptal stromal cells supply essential factors |
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Term
| Which cell types of stem cell are in colon? |
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Definition
| In the colon, LGR5+ stem cells at the crypt base generate rapidly proliferating TA cells in the lower half of the crypt. |
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Term
| What is the most successful method to grow small intestine stem cells in vitro? |
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Definition
| the most successful method is a Matrigel-based three-dimensional culture system that supports the growth of self-renewing, near-native intestinal epithelia in the absence of stromal niche components |
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Term
| Which types of stem cells could be found in bone marrow? |
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Definition
| HAEMATOPOIETIC & MESENCHYMAL STEM CELLS |
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Term
| Which types of niches are in bone marrow? |
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Definition
| quiescence,vascular,self-renewing |
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Term
| What are the characteristics of quiescence stem cells in bone marrow? |
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Definition
| Spindleshaped N-cadherin-expressing osteoblasts (SNOs) serve as niche cells to maintain quiescence and prevent differentiation of attached haematopoietic stem cells (HSCs). The quiescent endosteal niche would maintain dormant HSCs long-term. |
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Term
| What are the characteristics of vascular stem cells in bone marrow? |
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Definition
| In response to injury, quiescent HSCs might be activated and recruited to the vascular niche. |
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Term
| What are the characteristics of self-renewing stem cells in bone marrow? |
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Definition
| The self-renewing niche would contain quiescent HSCs intermingled with dividing HSCs. Self- renewing HSCs produce multipotential progenitors (MPPs) either by divisional or environmental asymmetry. |
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Term
| What factor do we need to reprogram neural cells? |
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Definition
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Term
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Definition
| Oct3/4, Sox2, Klf4, c-Myc |
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Term
| Name four strategies to induce reprogramming of somatic cells |
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Definition
1) Nuclear transfer (therapeutic cloning)
2) Cell fusion of somatic cells with ES cells results in the generation of hybrids that show all features of pluripotent ES cells
3)Explantation of somatic cells in culture selects for immortal cell lines
4)Reprogramming |
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Term
| What is TRANSDIFFERENTIATION? |
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Definition
| lineage reprogramming, is a process where one mature somatic cell transfor:s into another mature somatic cell without undergoing an intermediate pluripotent state or progenitor cell t-.e |
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