Notes - Introduction to Stem Cells Key Features of Stem Cells Stem cells a cell that can divide to give rise to both a new copy of itself and at least

Notes - Introduction to Stem Cells Key Features of Stem...

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1/18/17 Introduction to Stem Cells Key Features of Stem Cells Stem cells – a cell that can divide to give rise to both a new copy of itself and at least one specialized, differentiated, cell type Pluripotency – ability to differentiate into most cell types o Spectrum of potency states: Totipotent – able to form all cell types of the embryo and the adult, including germ cells and non-embryonic structures connected to the fetus Pluripotent – can do all of these things but is not able to form the non-embryonic structures Multipotent – able to form many but not all tissue cells of the body, can only form those cell types in the organs or tissue of the body in which they are normally located All other stem cells found in specialized tissue of the fetus or adult Unipotent – able to form just one other cell type Terminally differentiated – a specialized cell that produces all of the proteins required for its proper function within the tissue or organ it belongs to Can at best divide only a few times, but more often not at all Self-renewal – cells are capable of replicating and proliferating extensively without changing state Stem Cell Division Patterns: Self-Renewal Asymmetric vs symmetric All lines must relate back to one stem cell All lines must result in some cells remaining undifferentiated stem cells General Stem Cell Properties Pluripotency Self-renewal Clonality – ability to generate a population of stem cells from a single progenitor cell (this is a difficult concept to prove) Expression of characteristics transcription factors/molecular markers Machinery for rapid cell cycle progression o G1 period occurrence – done very quickly allowing rapid proliferation of cells Machinery for telomere maintenance o Stem cells can fill out the end of the chromosome ( the telomere – protective caps for the chromosomes) After cell division, these caps are shortened and once they are used up errors can occur leading to death of the cell The shorter the telomere, the “older” the cell o This means that stem cells have a high amount of telomerase activity Capacity to sense and respond to a wide variety of cell signaling systems (TGF-B, wnt, etc.) o Signals between neighboring cells as well as those cells that are far away 1/20/17 Introduction to Envisioned Stem Cell Uses new cell lines for research and testing drugs o indefinite cell growth in the lab o it is not easy to create immortal lines, usually the primary cells will begin to die after a finite amount of time/divisions
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o immortal = cells must be transformed done via either harvesting tumor cells or harvesting primary cells and treating them with something to transform them (virus, oncogene) o some cell types are very hard to immortalize or harvest or even grow in a lab setting stem cells bridge this problem new models to discover cell defects that underlie human genetic disease o want to know what, mechanistically, went wrong to cause genetic diseases o
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  • Spring '17
  • Cellular differentiation, Bone marrow

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