Apoptosis + Differentiation (Week 12)

Necrosis, apoptosis

Death can occur by __ (pathological, injury) or __ (normal turnover)

DNA, gene expression

All cells have the same __ makeup, however difference in function from differential __ __ upregulation/downregulation

Constitutive/Housekeeping Genes

Expression of genes regulate common functions

Morphogen Gradient

Facilitates early embryonic differentiation, via different concentration gradients

Stem Cells

New differentiated cells that can proliferate and differentiate into required cell types

Cell cycle

Not all tissues needed maintained stem cells, and still capable of proliferation via…

i.e. Skin fibroblasts, endothelial cells, epithelial cells, germ cells

Totipotent, blastula

__ cells means capable of becoming any type of embryonic or extra-embryonic cell

• Prior to __ stage (development)

Pluripotent, gastrulation

__ cells can become any embryonic cell (endoderm, ectoderm, mesoderm)

• When reach the blastula to __

Multipotent, adults

__ cells develop and differentiate into at least 2 different cell types

• When past gastrulation (in __ -stage of life)

Wnt, colorectal, intestinal, absorptive, goblet

Intestinal stem cells

• Stem cells at base of crypt/cellular indentation

• Regulated by __ signaling to keep in undifferentiated stem cell state

  • Transcription factor in __ cancer

• Daughter cell moves to __ surface

• Fully differentiated into __ or __ or enteroendocrine cells at surface

RBCs, macrophages, WBCs, multipotent

Bone marrow transplants - containing hematopoietic stem cells

• Differentiate into __s, __, __s, etc

• To counteract harsh chemotherapy killing healthy __potent cells

Embryonic-Derived Stem Cells (ESCs), totipotent

_____ are tissue-derived endogenous stem cells that contain hematopoietic cells, other multipotent cells

• Come from embryo due to unique __potent cell proliferation

Induced Pluripotent Stem cells (iPSCs)

Use adult patient somatic cells

Transcription factors, differentiate, cancer

iPSCs (pluripotent)

• Exposure to __ ___ by normal pluripotent stem cells in embryo

  • Then __ into any cell type

  • Less differentiated cells in higher numbers = Risk of __

Apoptosis

• Cellular condensation

• Requires ATP

• Cell phagocytosed by macrophages

• Ladder-like DNA fragmentation

• Individual cells affected

Apoptosis, necrosis

__ is a clean process that involves tightly regulated destruction

unlike __ 

(Apoptosis vs necrosis)

Chromatin, DNA, nucleus, blebs, cell membrane, inner, outer

Steps of Apoptosis

• (1) __ is condensed and __ is fragmented

• (2) __ is fragmented

• (3) Cells shrink and “__” form on cell surface

• (4) Cell is fragmented into apoptotic bodies each retaining a __ __

• (5) Phosphatidylserine (PS) translocated from the __ cell membrane leaflet to the __ leaflet

Caspases

Cytosine-containing aspartate-specific proteases

Cysteine, aspartate, pro-, inactivate, activate, disrupt

Caspases

• __ (AA) in active site, cleaves at __ (AA)!

• Start as “__-” then get to active form

• Activated caspases can - __ apoptotic inhibitors, __ cell structure disassembly, __ cytoskeleton regulation

External death, surface death, C8, C3

Extrinsic Pathway activating apoptosis

• Relies on __ __ signals

• Has cell __ __ receptors

• Uses __ (initiator) and __ (executioner)

damage, mitochondria, C9, C3

Intrinsic Pathway activating apoptosis

• Assess DNA __ and removes survival signals

• ONLY this uses __ (organelle)

• Uses __ (initiator) and __ (executioner)

Bad, Bax, Bak, mitochondrial

B cell lymphoma (BCL) Family Proteins

• Pro-apoptotic Initiator Proteins = __

• Pro-apoptotic Effector Proteins = __, __

  • Reside in outer __ membrane, maintain integrity of mitochondria

Bcl2, mitochondrial, cytosol, ER

B cell lymphoma (BCL) Family Proteins

• Anti-apoptotic proteins = __

  • Reside in outer __ membrane, the __, __ membranes

Positive, intrinsic, negative, intrinsic, extrinsic

Apoptosis Trigger Mechanisms

• Remove __ signals - Growth factor withdrawal (__)

• Receive __ signals - DNA damage (__), death signals (__)

Positive vs negative, then intrinsic vs extrinsic

BH3, Bcl2, Bax/Bqk, cytochrome c, caspase, apoptosis

Intrinsic Pathway Basics

• __ proteins sense stress → Inhibits __ → Activates __/__

• Leakage of cyto__ __ → __ activation → Net __

Akt, Bad, Inactive, Bax/Bad, C, C9, NO

Intrinsic Pathway Trophic Factor Present

• PI-kinase phosphorylates __

• Akt phosphorylates __

• Bad is __ (active/inactive)

• Bcl2 inhibits __/__

• Cytochrome _ remains in mitochondria

• C_ activity means __ (is/no) apoptosis

Akt, Bad, active, Bax/Bak, C, C3, is

Intrinsic Pathway Trophic Factor Absent

• PI-kinase not activated and __ is NOT phosphorylated

• Akt NOT phosphorylated to __

• Bad is __ (active/inactive) and releases inhibition of __/__

• Cytochrome _ released in mitochondria

• C_ activity means __ (is/no) apoptosis

External, signal, L, Fas, C3

Extrinsic Pathway

• Requires __ factor (death __) for initiation

• Fas_ binds to __ receptor

• Active C__ →  + Apoptosis

Caspases, ubiquitin ligases

Inhibitors of Apoptosis (IAP) - Endogenous inhibitors

• Bind to __ (enzyme) → Decreased catalytic activity

• __ __ (enzyme) for degradation

SMAC/DIABLO, IAPs

__ are pro-apoptotic protein located in mitochondria

• When released in cytoplasm, inhibits __s → Favors apoptosis

Bcl2, IAPs

p53 inhibits apoptosis inhibitors (__, __)

• “Inhibitor of inhibitors”

Excessive, hypoxia

__ apoptosis = tissue damage due to __ (i.e. MIs, strokes, neurodegenerative disease)

Totipotent

Which is the best term for stem cells that are capable of becoming ANY type of cell, whether embryonic or extraembryonic?

Chromosome 4, trinucleotide repeats, inclusions, aggregation, aggregation, precipitation

Huntington’s Disease

• Huntingtin gene is on __ _

• __ __: Mutation to gene on chromosome 4 translocates to nucleus

• Nucleus - __ from oligomerization and __ disrupt transcription in nerve tissue

• Cytoplasm - __ and __ alters metabolism and intracellular/extracellular signaling

mHTT, p53, C6

Huntington's Disease

• __ (gene) triggers apoptosis via C6 to neurons and skeletal muscle

• Also upregulated __ protein → Increase C_ to favor apoptosis

Kindergarten effect

Paracrine death signals can lead to neighboring cells undergoing apoptosis