STEM CELL BIOLOGY

STEM CELL BIOLOGY

1. WHY?

   • STEM CELLS: Unique Ability to Renew, Can Differentiate into Specialized Cells
   • RESEARCH
     • 1. Identify Drug Targets
       • 2. Toxicity Testing
         • 3. Tissues & Cells for Transplantation
           • 4. Study Cell Differentiation
   • GROWING COMMERCIALIZATION
     • Aging: losing ability to regenerate
     • Stem Cell: Unique Ability for Regeneration

2. BACKGROUND

   • GENETICS AND DEVELOPMENT
     • Humans & Animal Embryos = Similar Stages Of Early Development
       • All vertebrates = same 3 germ layers (endoderm, mesoderm, endoderm)
         • THEN WHY DO HUMANS & ANIMALS DIFFER?
           • Differential Modulation of Genes
             • Mostly in Non-Coding Genome
             • Regulatory DNA
               • Combinatorial Control Of Gene Expression
                 • Same Signal = Different Outcomes
                 • Cell Memory = Retention of Epigenetic Marks
                   • Epigenetics = heritable changes in gene expression
                     • Three Major Mechanisms of Epigenetic Regulation
                       • 1. Histone Modifications via Phosphorylation, Methylation or Acetylation
                       • 2. DNA Methylation
                       • 3. RNA Modification

3. PAST THEORIES

   • Epigenesis: various stages >> new structures
     • Aristotle: 4th Century BC
   • Preformation: existing structures >> get bigger
     • Malphigi's reasoning: un-incubated egg = lot of structure

4. TERMINOLOGY

   • Totipotent: ability to form all cell types of embryo + adult
     • Germ cells
     • Nonmebryonic structures connected to fetus
   • Pluripotent: ability to form all cell types except extra-embryonic tissue

5. CELL FATE

   • 1. TOTIPOTENT
     • 2. PLURIPOTENT
       • 3. MULTIPOTENT
         • 4. OLIGO, UNIPOTENT PROGENITORS
           • 5. DIFFERENTIATED CELLS

6. REFLECTION

   • Key Point: Introduction of Stem Cells
   • What did I learn:
     • New terminology & Distinction between totipotent, pluripotent, multipotent, unipotent cells
     • Learned about steps that cells undergo before becoming differentiated
     • Implications & Variety of Ways in Which Stem Cell Research can be utlized
     • Ancient Prevaient Theories about Stem Cells
     • Importance of Epigenetic Regulation in Cell Fate