positive regulation of apoptotic cell clearance

Definition

Target type: biologicalprocess

Any process that activates or increases the frequency, rate or extent of apoptotic cell clearance. [GOC:obol]

Positive regulation of apoptotic cell clearance is a tightly controlled biological process that ensures the safe and efficient removal of dying cells from the body. This process is crucial for maintaining tissue homeostasis and preventing inflammation.

Here's a detailed description of the process:

1. **Apoptosis Initiation**: The process begins with the activation of intrinsic or extrinsic apoptotic pathways, leading to the activation of caspases and the dismantling of the cell. This dismantling includes:
* **DNA fragmentation**: Caspases cleave DNA into smaller fragments, causing the characteristic ladder-like appearance on electrophoresis.
* **Cell surface changes**: Phosphatidylserine (PS), a phospholipid normally found on the inner leaflet of the cell membrane, is flipped to the outer leaflet.
* **Formation of apoptotic bodies**: The cell breaks down into membrane-bound apoptotic bodies containing cellular components.

2. **Apoptotic Cell Recognition**:
* **PS exposure**: The exposed PS on the apoptotic cell surface acts as an "eat me" signal, recognized by phagocytes.
* **Other signals**: Apoptotic cells also express other molecules like calreticulin, oxidized lipids, and ATP, which further facilitate their recognition by phagocytes.

3. **Phagocytosis**:
* **Engagement of receptors**: Phagocytes express a variety of receptors that recognize the signals on apoptotic cells, including:
* **Phosphatidylserine receptors**: Tim4, BAI1, and other receptors specifically bind to PS.
* **Other receptors**: Macrophages also express receptors for calreticulin, oxidized lipids, and ATP.
* **Internalization**: Upon receptor engagement, phagocytes engulf the apoptotic cell.

4. **Apoptotic Body Degradation**: Once inside the phagocyte, apoptotic bodies are broken down and their components are recycled.

5. **Immune Modulation**: Phagocytosis of apoptotic cells is a critical event in immune regulation, as it prevents the release of intracellular contents that could trigger an inflammatory response. This is achieved by:
* **Anti-inflammatory cytokine production**: Phagocytes release anti-inflammatory cytokines, such as IL-10, to suppress inflammation.
* **Induction of tolerance**: The phagocytosis of apoptotic cells can also induce immune tolerance, preventing the development of autoimmune responses.'
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Proteins (2)

Compounds (5)