Regenerative Medicine & Biotechnology: Stem Cell Biology II

Flashcards covering stem cell biology fundamentals, the mechanics of iPSCs, immunological components, and regenerative applications in diabetes, neurology, and cardiology.

Stem Cells

Cells pivotal to animal development, adult maintenance, and regeneration after injury characterized by the ability to self-renew and give rise to differentiated progeny.

Self-renew

The ability of stem cells to divide to make copies of themselves for a prolonged period of time without differentiating.

Asymmetric Cell Division

A key feature of stem cells where they give rise to either differentiated or committed progeny, or both a copy of themselves and a differentiated cell.

Totipotent

The developmental potential of a zygote, representing the highest level of cellular potency.

Pluripotent

The developmental potential of embryonic stem (ES) cells, capable of giving rise to cells related to all 3 germ layers: ectoderm, mesoderm, and endoderm.

Multipotent

Adult stem cells that possess limited developmental potential and are restricted to specific tissue types.

iPSCs (Induced Pluripotent Stem Cells)

Cultured somatic cells, commonly fibroblasts, transduced with vectors expressing stem cell genes to de-differentiate and re-gain stemness.

Yamanaka Protocol

A method for generating iPSCs from differentiated somatic cells by restoring pluripotency using specific transcription factors.

Germ Layers

The three early embryonic layers: Ectoderm (brain, nerves, skin), Mesoderm (muscles, heart, blood), and Endoderm (gut, lungs, bladder).

Somatic Cell Nuclear Transfer (SCNT)

A technique used to clone Dolly the Sheep where a differentiated nucleus is transplanted into an enucleated egg cell to reverse differentiation.

Yamanaka Factors

The four transcription factors sufficient to restore pluripotency in human and mouse fibroblasts: $Myc$, $Oct3/4$, $Sox2$, and $Klf4$.

Nanog

A Homeobox-family transcription factor important in pluripotency and self-renewal that is induced by LIF in mouse ES cells via $Stat3$ activation.

Antibody

A Y-shaped protein secreted by B cells in response to an antigen that binds specifically to eliminate infectious organisms.

Antigen

A substance, often a protein, found on the surface of infectious organisms or organ transplants that induces the formation of an antibody.

Antigen Presenting Cells (APC)

Cells within the body that process antigens and display them on their surface in a form recognizable by T cells.

Autoimmune Disease

A condition resulting from the formation of antibodies that attack the cells or tissues of an individual's own body, such as Lupus or Type 1 diabetes.

B cells

Also known as B lymphocytes, these cells mature into plasma cells to secrete large amounts of specific antibodies when stimulated.

Bone Marrow

Soft tissue that contains hematopoietic stem cells (for all blood cells) and mesenchymal stem cells (for types like chondrocytes producing cartilage).

Cytokines

Regulatory proteins produced and secreted by cells primarily used for communication, such as interleukins in an immune response.

Memory Cells

A subset of antigen-specific T or B cells that recall prior exposure to an antigen to respond quickly without requiring new activation.

Major Histocompatibility Complex (MHC)

A group of genes coding for cell-surface antigens that are the primary reason organ and tissue transplants from incompatible donors fail.

CD4 Helper T cells

Lymphocytes instrumental in initiating an immune response by supplying special cytokines; these are destroyed by the HIV virus in AIDS patients.

CD8 Cytotoxic T cells

Also known as killer T cells, these are activated by CD4 helper cells and are capable of killing infected cells in the body.

Thymus

A lymphoid organ in the upper chest where maturing T cells are educated to discriminate between self and nonself proteins.

Tolerance

A state of specific immunologic unresponsiveness where individuals are normally tolerant of their own body's cells and tissues.

Gene Therapy

The genetic modification of cells to produce a therapeutic effect, often involving transferring DNA containing a therapeutic gene into cells.

Islet of Langerhans

The functional unit of the endocrine pancreas containing the beta cells that synthesize and secrete insulin.

Beta Cell

Pancreatic cells located adjacent to blood vessels that respond to changes in blood glucose concentration by adjusting insulin production.

Neuron

A nervous system cell consisting of a cell body, dendrites, and an axon, which releases neurotransmitters into synapses.

Parkinson's Disease

A disease where dopamine-releasing neurons in the nigro-striatal pathway (from the substantia nigra to the striatum) degenerate.

Oligodendrocyte

A type of nervous system cell that supplies axons with an insulating myelin sheath.

Amyotrophic Lateral Sclerosis (ALS)

Also known as Lou Gehrig's disease, this progressive disorder destroys motor neurons in the spinal cord, leading to paralysis.

Myocardial Infarction

An event occurring when a coronary artery is ligated or blocked, inducing an infarct in the heart muscle.

RNAi (RNA interference)

A technique using artificial $siRNA$ delivered by lipid molecules to target specific genes in a stem cell for silencing.

RISC (RNA-Induced Silencing Complex)

A complex that cleaves $mRNA$ or causes ribosomes to stall depending on the complementarity of the $siRNA$ strands.

Slicer

An enzyme that cleaves the $mRNA$ when the two RNA strands are perfectly complementary in the RNAi process.

CRISPR-Cas9

A genome-editing tool where PAM sequences recruit and activate the Cas9 endonuclease to perform targeted DNA modifications.

Blastocyst

The early embryo stage (Day 5) containing the inner cell mass from which cultured pluripotent stem cells are derived.