Several mechanisms prevent cell death, depending on the type of cell and the cause of potential death. Cell death can be prevented through the inhibition of apoptosis (programmed cell death) or by protecting cells from damage leading to necrosis (unprogrammed cell death).
Mechanisms Preventing Cell Death:
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Inhibition of Apoptosis: Certain proteins actively block programmed cell death. The Bcl-2 family of proteins, for example, including Bcl-2 and Bcl-XL, inhibit apoptosis by preventing the release of cytochrome c from mitochondria (as noted in the provided reference). Other proteins like Orco, discovered in ants, also seem to play a role in preventing cell death while being vital to other functions such as smell neuron function and development (as found in this NYU and University of Florida research).
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Protection from Damage: Preventing cell damage is crucial to avoid necrosis. This can involve multiple approaches, such as:
- Reducing oxidative stress: Proteins like DJ-1 play a role in antioxidative stress, preventing cell death caused by oxidative damage (EMBO report).
- Repairing damaged cellular components: The body has mechanisms for repairing DNA damage and other forms of cellular injury.
- External interventions: Medical interventions, such as the use of intracisternal cyclodextrin in treating Niemann-Pick type C1 disease, can help prevent cerebellar dysfunction and Purkinje cell death (Sci Transl Med). Exogenous administration of inter-α inhibitor proteins (IAIPs) has shown promise in preventing cell death after stroke (JCI). A compound developed by WEHI scientists acts as a "cell death blocker," keeping cells alive when they otherwise would have died (WEHI news).
- Regulation of Immune Response: The immune system plays a role in maintaining cellular health and preventing excessive death. For example, the linear ubiquitin chain assembly complex (LUBAC) prevents lethal dermatitis by inhibiting cell death induced by TNF (Nature). Similarly, the accumulation of intestinal Foxp3+ regulatory T cells (Treg cells) in response to microbiota is a regulated process where tolerance, and therefore cell survival, is tightly controlled (Nature Immunology).
Conclusion:
Preventing cell death is a complex process involving various cellular and systemic mechanisms. Understanding these mechanisms is critical in developing therapies for various diseases and conditions involving cellular damage and death.