Stem Cells Lecture Review

Flashcards covering key vocabulary, definitions, and concepts related to stem cells, their types, regulation, niches, and applications in regenerative medicine and organoid technology, based on the provided lecture notes.

Stem Cells

Undifferentiated cells that can differentiate into specialized cells and can divide (through mitosis) to produce more stem cells.

Self-renewal

A stem cell’s ability to divide and in doing so produce a replica of itself.

Potency

The power of a stem cell to produce many different types of differentiated cells.

Asymmetric division

A type of cell division that allows stabilizing the stem cell pool and generating a daughter cell that goes on to differentiate.

Multipotent

Capable of forming numerous types of cells or cell types specific for a given tissue.

Committed cell

A cell that makes one or very few types of cells.

Progenitor cell

A cell that can proliferate multiple rounds of divisions but is transient in its life and is committed to becoming a particular type of differentiated cell.

Unipotent stem cells

Stem cells that generate only one cell type, e.g., spermatogonia.

Totipotent stem cell

A stem cell capable of producing all the cells of the embryo and the first 4 to 8 cells.

Pluripotent stem cells

Stem cells capable of producing all the cell types of a lineage.

Hematopoietic Stem Cells (HSCs)

Blood-forming stem cells not capable of unlimited self-renewal; they divide only a few times before differentiating.

Stem cell niche

The microenvironment that surrounds and regulates a stem cell, controlling its self-renewal, survival, and differentiation of progeny.

Inner Cell Mass (ICM)

A cluster of cells within the blastocyst that becomes the embryo and contains embryonic stem cells.

Trophectoderm (Trophoblast)

The outer cells of the morula/blastocyst that differentiate to form extraembryonic structures like the placenta and chorion.

Oct4, Nanog, Sox2

Essential transcription factors that are critical for promoting and maintaining pluripotency in Inner Cell Mass (ICM) cells.

Cdx2

A transcription factor whose expression is upregulated in the outer cells of the morula to promote trophectoderm differentiation and repress epiblast development.

Hippo signaling

A critical signaling cascade, starting with cell-to-cell interactions and cell adhesion molecules, that controls organ size and development of the inner cell mass and trophectoderm.

Ventricular-Subventricular Zone (V-SVZ)

One of two principal regions in the adult mammalian cerebrum where neural stem cells (NSCs) have been characterized, located along the lateral ventricles.

Subgranular Zone (SGZ) of the hippocampus

One of two principal regions in the adult mammalian cerebrum where neural stem cells (NSCs) have been characterized.

B cells (Neural Stem Cells)

Subtypes of neural stem cells in the V-SVZ niche, where Type 1 B cells are quiescent and Types 2 and 3 are actively proliferating.

Ependymal cells (E cells)

A type of neuroglia in the central nervous system, forming a layer along the ventricular wall within the V-SVZ niche.

VCAM1

A cell adhesion molecule that colocalizes with GFAP in neural B cells at the pinwheel core, and whose adhesion is crucial for maintaining pinwheel organization.

Notch activity (in V-SVZ)

High levels support neural stem cell quiescence, while decreasing or oscillating levels promote progenitor proliferation and maturation toward neural fates.

Hematopoiesis

The biological process involving the generation of all types of blood cells from hematopoietic stem cells (HSCs).

Endosteal niche

A subniche within the hematopoietic stem cell (HSC) niche where long-term quiescent HSCs adhere to osteoblasts.

Perivascular niche

A subniche within the hematopoietic stem cell (HSC) niche where short-term active HSCs are associated with oxygen-rich blood vessels.

CXCL12

A signaling molecule from CAR cells and mesenchymal stem cells; increased exposure transitions HSCs into proliferative behavior, while downregulation encourages HSC migration.

Mesenchymal Stem Cells (MSCs)

Stem cells with a surprisingly large degree of plasticity, found in various connective tissues, playing dual roles as supportive stromal cells and multipotent stem cells.

Embryonic Stem Cells (ESCs)

Pluripotent stem cells derived from the Inner Cell Mass (ICM) of an embryo, which can be maintained in culture indefinitely and differentiate into any cell type of the body.

Induced Pluripotent Stem Cells (iPS cells)

Somatic cells that have been reprogrammed back into an embryonic stem cell-like pluripotent state using defined sets of transcription factors, pioneered by Shinya Yamanaka.

Yamanaka factors

A specific set of four transcription factors (Oct3/4, c-Myc, Sox2, Klf4) used to reprogram differentiated somatic cells into induced pluripotent stem cells (iPSCs).

Organoid

Rudimentary 'mini-organs' cultured in a dish from pluripotent stem cells (ESCs, iPSCs) or adult stem cells, designed to mimic embryonic organogenesis and multicellular hallmarks of human organs.

Cerebral organoids

Organoids specifically designed to model human brain development and diseases like microcephaly, allowing for studies of patient-specific tissue progression in vitro.