myeloid cell apoptotic process

Definition

Target type: biologicalprocess

Any apoptotic process in a myeloid cell, a cell of the monocyte, granulocyte, mast cell, megakaryocyte, or erythroid lineage. [CL:0000763, GOC:add, GOC:mtg_apoptosis, PMID:11292031, PMID:15330259, PMID:17133093]

Myeloid cell apoptosis is a tightly regulated process that eliminates unwanted or damaged myeloid cells, ensuring immune homeostasis and preventing uncontrolled inflammation. It involves a cascade of molecular events leading to the dismantling of the cell.

**Initiation:**
- **Extrinsic pathway:** This pathway is triggered by external signals, such as death receptor activation (e.g., TNF-α, Fas ligand) on the cell surface. Binding of these ligands leads to the formation of death-inducing signaling complex (DISC) and activation of caspase-8.
- **Intrinsic pathway:** This pathway is activated by intracellular stress signals, such as DNA damage, oxidative stress, or growth factor deprivation. These signals trigger the release of cytochrome c from mitochondria into the cytoplasm, leading to the formation of the apoptosome and activation of caspase-9.

**Execution:**
- **Caspase activation:** Both pathways converge on the activation of caspase-3, a key executioner caspase. Once activated, caspase-3 cleaves and activates other caspases, initiating a cascade of proteolytic events.
- **Cellular dismantling:** Activated caspases dismantle the cell, leading to characteristic apoptotic features:
- **Nuclear fragmentation:** Caspase-activated DNase (CAD) degrades DNA, resulting in the characteristic ladder-like pattern seen on DNA electrophoresis.
- **Cell shrinkage:** Cells lose volume and become more compact due to the degradation of the cytoskeleton and other cellular components.
- **Blebbing:** The cell membrane forms bulges (blebs) as the cytoskeleton collapses.
- **Apoptotic body formation:** The apoptotic cell fragments into membrane-bound vesicles (apoptotic bodies) containing cellular debris.

**Phagocytosis:**
- Apoptotic bodies are rapidly recognized and engulfed by phagocytes, such as macrophages. This prevents the release of intracellular contents and inflammation.

**Regulation:**
- Myeloid cell apoptosis is tightly regulated by a complex interplay of pro- and anti-apoptotic factors.
- Pro-apoptotic proteins (e.g., Bax, Bak) promote the release of cytochrome c from mitochondria.
- Anti-apoptotic proteins (e.g., Bcl-2, Bcl-xL) inhibit this release and promote cell survival.

**Importance:**
- Myeloid cell apoptosis is crucial for maintaining immune homeostasis, preventing autoimmunity, and regulating inflammation.
- Dysregulation of apoptosis can contribute to the development of various diseases, including cancer, autoimmune disorders, and infections.
- Understanding the molecular mechanisms of myeloid cell apoptosis is crucial for developing novel therapeutic strategies for these diseases.'
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Proteins (4)

Compounds (36)