Stems cells (hESCs and hIPSCs)

Blastula / Blastocyst

Source of (embryonic) stem cell lines that are donated from IVF. Consists of approximately 150 cells and 3 to 5 days post-fertilization.

Totipotent

Potency in which it can become any cell type, including placental (i.e. make a whole new organism). Potency of zygotes and Morula.

Pluripotent

Potency in which it can become any cell type (excluding placental). Potency of blastula.

Multipotent

Progenitor cells that have specificity. Found in both kids and adults.

Unipotent

Can only become one specific cell type.

Terminally differentiated

Cells that are “unable” to divide (or at least divide very slowly). Include neurons, cardiomyocytes, epithelial cells, and adipocytes.

Gastrula

Embryonic development stage after blastula. Has 3 layers: Ectoderm, Mesoderm, and Endoderm.

Ectoderm

External layer of gastrula. Cells in this layer are precursors for skin cells of the epidermis, neurons of the brain, and pigment cells.

Mesoderm

Middle layer of gastrula. Cells in this layer are precursors of cardiac muscle, skeletal muscle cells, tubule cells of kidneys, red blood cells, smooth cells.

Mesenchymal cells

Cells that stem from the mesoderm. Do not have immunomarkers on them (so no immune response). Include bone, cartilage, and fat.

Hematopoietic cells

Mesenchymal cells derived from bone marrow. Include RBC, WBC, and platelets.

Feeder cells

Layer of fibroblasts that causes ESC to not spontaneous differentiate.

Cloning

Removing the nucleus of an unfertilized egg and replacing it with the nucleus of the same organism (if a human, nucleus of another person)

Adult stem cells

Somatic or progenitor cells. These cells are undifferentiated and divide to replenish dying cells and regenerate damaged tissue. Found in all tissues and have a limited capacity to divide.

Neural cells

neurons, astrocytes, and oligodendrocytes.

Quiescent

Dormant cells that do not divide unless needed.

Transdifferentiation

Ability of adult stem cells to differentiate into other tissue types than what is predicted by cell lineage.

Induced Pluripotent Stem Cells (IPSCs)

Achieved by Shinya Yamanaka in 2006. Dedifferentiation of unipotent cells (ex fibroblasts) to pluripotent cells. Done through transfecting with a virus and increasing the expression 4 genes.

Transfection

Delivery of genes to a cell. Typically done through viruses (best as iPSCs are autologous). Can be done with a lipid nanoparticle or a polymer.

Induced Pluripotency genes

c-Myc (oncogene), Sox 2, KlF 4, and Oct 4

Transcription factors of hESCs

Oct 4, NANOG, and Rex 4

Cell markers of hESCs

SSEA-3, SSEA-4, TRA-60, and TRA-1-81

Safety of iPSCs

Can’t be immunogenic, cancerous, or cytotoxic. Cells must be contained or fully differentiated, stay alive long enough to be effective, free of pathogens, and integrate with native environment.