Protective effects of pituitary adenylate cyclase-activating polypeptide (PACAP) against apoptosis
Tommy Seaborn1, Olfa Masmoudi-Kouli, Alain Fournier
1Department of Pediatrics, Laval University, St-François d’Assise Hospital Research Center, Québec, Canada.
Abstract:
Apoptosis is a regulated process leading to cell death, which is implicated both in normal development and in various pathologies including heart failure, stroke and neurodegenerative diseases. Caspase-3, a key enzyme of the apoptotic pathway, is considered as a major target for the treatment of abnormal cell death. Many factors that inhibit cell death have been identified, but the mechanisms involved are not always fully understood. Pituitary adenylate cylase-activating polypeptide (PACAP) has been shown to exert neuroprotective activities during development. PACAP also inhibits apoptosis in cardiomyopathy, decreases glutamate-induced retinal injury, reduces neuronal loss in case of stroke, and prevents ethanol neurotoxicity. Most of the antiapoptotic effects of PACAP are mediated through the PAC1 receptor. This receptor activates a transduction cascade of second messengers to stimulate Bcl-2 expression which inhibits cytochrome c release and blocks in turn caspase activation. PACAP also acts through the PI3K/Akt pathway and inhibits the expression of proapoptotic factors such as c-Jun or Bax. The remarkable effect of PACAP on the apoptotic cascade suggests that innovative PACAP derivatives could potentially be useful for treatment of post-traumatic lesions, chronic neurodegenerative diseases, cardiac ischemia and/or retinopathy.
Insights
Pituitary adenylate cyclase-activating polypeptide (PACAP) inhibits apoptosis, a key process in cell death and disease. PACAP derivatives show potential for treating neurodegenerative diseases and cardiac conditions.
Area of Science:
- Molecular Biology
- Neuroscience
- Cardiology
Background:
- Apoptosis, or programmed cell death, is crucial in development and disease, with caspase-3 as a key target.
- Pituitary adenylate cyclase-activating polypeptide (PACAP) exhibits neuroprotective effects and inhibits apoptosis in various conditions.
Purpose of the Study:
- To elucidate the antiapoptotic mechanisms of PACAP.
- To explore the therapeutic potential of PACAP derivatives in diseases involving abnormal cell death.
Main Methods:
- Investigated PACAP's effects on apoptotic pathways.
- Examined PACAP's interaction with PAC1 receptor and downstream signaling (Bcl-2, PI3K/Akt).
Main Results:
- PACAP inhibits apoptosis via the PAC1 receptor, stimulating Bcl-2 expression and blocking caspase activation.
- PACAP also acts through the PI3K/Akt pathway, reducing proapoptotic factors like c-Jun and Bax.
Conclusions:
- PACAP effectively modulates the apoptotic cascade through multiple pathways.
- Novel PACAP derivatives may offer therapeutic benefits for conditions like neurodegenerative diseases, stroke, and cardiac ischemia.
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