retinal cell apoptotic process

Definition

Target type: biologicalprocess

Any apoptotic process in a retinal cell. [GOC:mtg_apoptosis, PMID:15558487, PMID:24664675]

The retinal cell apoptotic process is a complex and tightly regulated sequence of events that culminates in the programmed death of retinal cells. This process is essential for normal retinal development and homeostasis, and its dysregulation can contribute to various retinal diseases.

**Initiation:**

- **Intrinsic pathway:** This pathway is triggered by intracellular stressors such as DNA damage, oxidative stress, and growth factor deprivation. These stressors activate pro-apoptotic proteins like Bax and Bak, which permeabilize the mitochondrial outer membrane and release cytochrome c into the cytosol. Cytochrome c then binds to apoptotic protease activating factor 1 (Apaf-1) and procaspase-9, forming the apoptosome, which activates caspase-9.
- **Extrinsic pathway:** This pathway is triggered by extracellular signals like death receptors (e.g., Fas, TNF-α receptor) on the cell surface. Ligands like FasL and TNF-α bind to these receptors, activating caspase-8.

**Execution:**

- **Caspase cascade:** Both intrinsic and extrinsic pathways ultimately converge on the activation of caspases, a family of cysteine proteases. Caspase-9 and caspase-8 are known as initiator caspases, while caspases-3, -6, and -7 are executioner caspases. Initiator caspases activate executioner caspases, which then cleave and activate various cellular substrates, leading to the dismantling of the cell.
- **Cellular dismantling:** Executioner caspases induce a series of morphological changes characteristic of apoptosis. These include:
- **Nuclear fragmentation:** Caspases cleave nuclear lamins, leading to nuclear envelope breakdown and DNA fragmentation.
- **Cell shrinkage:** Caspases degrade cytoskeletal proteins, causing the cell to shrink and condense.
- **Blebbing:** Caspases cleave membrane proteins, resulting in the formation of apoptotic blebs, membrane-bound vesicles containing cellular debris.

**Phagocytosis:**

- **Apoptotic bodies:** Cells undergoing apoptosis break down into apoptotic bodies, which are readily engulfed by phagocytes. This process prevents the release of cellular contents into the surrounding environment, minimizing inflammation and tissue damage.
- **Removal of apoptotic cells:** The phagocytosis of apoptotic bodies by macrophages and other phagocytes is crucial for maintaining tissue homeostasis and preventing inflammation.

**Role in Retinal Development and Disease:**

- **Retinal development:** Apoptosis is essential for the elimination of excess cells during retinal development, ensuring the precise formation of the retinal layers and their connectivity.
- **Retinal degeneration:** Dysregulation of the apoptotic process can lead to excessive cell death, contributing to retinal degeneration in diseases like retinitis pigmentosa, age-related macular degeneration (AMD), and diabetic retinopathy.

The detailed molecular mechanisms involved in retinal cell apoptosis vary depending on the specific cell type, the triggering stimulus, and the stage of retinal development. Understanding these mechanisms is crucial for developing therapies to prevent or delay retinal degeneration and preserve vision.'
"

Proteins (1)

Compounds (5)