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Understanding Stem Cells

Understanding Stem Cells. Stem cells have the ability to divide for indefinite periods in culture to give rise to specialized cells. Potency. Totipotent: unlimited Pluripotent: little limitation Multipotent: highly limited. Stem Cell Origins. hASC’s . . . Adult Stem Cells

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Understanding Stem Cells

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  1. Understanding Stem Cells • Stem cells have the ability to divide for indefinite periods in culture to give rise to specialized cells

  2. Potency • Totipotent: unlimited • Pluripotent: little limitation • Multipotent: highly limited

  3. Stem Cell Origins • hASC’s . . . Adult Stem Cells • hEGC’s . . . Fetal Stem Cells • hESC’s . . . Embryonic Stem Cells • Now iPS cells • Where do these 3 lines come from?

  4. Applications of Stem Cells • Understanding complex developmental events • drug development and safety • generation of cells and tissues for therapy • heart muscle transplants • islet cells in the pancreas

  5. Cloning and Stem Cells • Immune rejection/tissue incompatibility may be overcome by SCNT (cloning) • Using a person’s own cells to generate stem cells could eliminate rejection

  6. All stem cells are NOT alike Do ASC’s have the same potential as ESC’s? NO . . . Maybe?

  7. Why not just pursue hASC’s? • Positive aspect of ASC’s is lack of tissue rejection and ethical issues • Negative aspects: • apparent limitations to specialization • lack of available quantities and lines • age of cells • Can this be overcome?

  8. More Thoughts . . . • Funding for SC research: pending legislation, ethics, economy, etc. • Funding for IVF clinics (political and ethical debates) • The pressure is on legislatively • Americasdebate.com

  9. How Do We Grow Cells in a Laboratory? To study cells, they must be grown outside of an individual, in an artificial environment. To survive outside of an organism, cells must be “fed” and cared for : 1. Nutrient soup: amino acids, carbohydrates, fats, vitamins, minerals, intact proteins 2. Incubator: temperature must be kept within limits characteristic of organism Cultured cells Plastic dish

  10. What Starts the Process of Differentiation? The purple cells are descended from a single cell and are genetically identical to each other. They all have exactly the same DNA sequence in their chromosomes. How can these cells have different fates?

  11. What Starts the Process of Differentiation? At the eight-cell stage, “compaction” occurs, creating an inner and outer layer of cells. outer cell layer inner cell layer These cells still have identical genomes. But their environments have changed.

  12. A Division B • Cell Division:change gene expression, make more cells-- also called “proliferation” • Differentiate (specialize): change gene expression, become a different type of cell C G F A Differentiation B C E D Signals Can Activate Different Parts of the Genome • Cells decide what to do based on chemical & physical stimuli or “signals” from • Inside the cell (genome, cytoplasm) • Outside the cell (environment: other cells, hormones)

  13. Follow the Yellow Brick Road…. Huh? Theme: Pathways First, the BIG picture: An overview of the big Stem Cell Pathway Picture.

  14. How To Grow Stem Cells How To Grow Stem Cells 1 5 3 4 2 • In vitro fertilized egg or egg made from nucleus transfer • Blastocyst forms (5-7 days) • Inner stem cell mass • Undifferentiated stem cells cultivated in petri dish • Red blood cells • Nerve cells • Muscle cells 6 7

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