Vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptides (PACAP27) and PACAP38) protect CD4+CD8+ thymocytes from glucocorticoid-induced apoptosis.
Delgado. M M; Garrido. E E; Martinez. C C; Leceta. J J; Gomariz. R P RP
Key Findings
- VIP, PACAP27, and PACAP38 prevent glucocorticoidâinduced DNA fragmentation and cell death in rat thymocytes, with peak effect at 10â»âžâ10â»âčâŻM.
- The VIPâreceptor antagonist [NâAcâTyrÂč,DâPheÂČ]âGRF(1â29) amide partially reverses the protective effect, indicating a VIP1âR mediated mechanism.
- Protection is strongest in doubleâpositive (CD4âșCD8âș) thymocytes, suggesting a role in Tâcell maturation.
Practical Outcomes
- For biohackers, the data suggest that using GRFâ1â29 could blunt the natural immuneâprotective actions of VIP/PACAP during stress, potentially affecting thymic Tâcell development. While not a direct protocol, it warns that combining GRFâ1â29 with highâdose glucocorticoids or stressâreduction strategies may have unintended immune consequences. More research is needed before any dosage recommendations.
Summary
The study shows that two brainâderived peptides, VIP and PACAP, can protect young immune cells (CD4+CD8+ thymocytes) from dying when the body releases stress hormones like dexamethasone. When a short fragment of a related peptide, called GRFâ1â29, blocks the VIP receptor, this protection is reduced, proving the effect works through that specific receptor.
Abstract
In the present study, the effects of vasoactive intestinal peptide (VIP) and the pituitary adenylate cyclase-activating polypeptides, PACAP27 and PACAP38, in a concentration range from 10(-13) to 10(-6) mol/L were studied in vitro on the spontaneous and dexamethasone (DEX)-induced apoptosis in rat thymocytes. The results show that VIP and both PACAPs inhibit significantly and in a similar way the DNA fragmentation characteristic of glucocorticoid-induced apoptosis and increase the cell survival of thymocytes, with a maximal effect observed at 10(-8) to 10(-9) mol/L. This study showed the ability of the VIP-receptor (VIP-R) antagonist [N-Ac-Tyr1,D-Phe2]-GRF(1-29) amide to partially reverse the inhibitory effect of VIP and both PACAPs on DEX-induced apoptosis, providing evidence for a specific VIP1-R-mediated response and supporting the involvement of a single receptor for the three neuropeptides. Phenotypic analysis showed that VIP, PACAP27, and PACAP38 protect predominantly CD4+CD8+ thymocytes from glucocorticoid-induced apoptosis. These findings suggest that these neuropeptides could be involved in intrathymic T-cell maturation.
Study Information
pubmed
1996
1996-06-15T00:00:00.000Z