PH_II_P: Pharmaceutical Sciences II. Posters
Kamilla Varga1, Fruzsina Bagaméry1, Alexandra Paszternák1, Éva Szökő1, Tamás Tábi1
Department of Pharmacodynamics, Semmelweis University, Budapest
Introduction: Resveratrol has been recently extensively examined, due to several reports on its diverse pharmacological effects, however the underlying mechanisms are still not clear. In our previous studies, resveratrol was found to be a major cell protective agent in non-transformed cells, and was able to prevent the caspase activation in serum free conditions. In the investigation of the possible pathways, we have found that inducing stress-resistance mechanisms may play a key role.
Aim: In this present work we aimed at studying the structure-activity relationships by examining analogues with different oxidation states. In addition, we wanted to elucidate the possible pathways.
Methods: Apoptosis was triggered by serum deprivation in primary mouse embryonal fibroblasts. Caspase-3 activity was measured by using its fluorogenic substrate. Reactive oxygen species production, mitochondrial membrane depolarization and autophagy flux were determined by their fluorescent indicators: hydroethidine, JC-1 and acridine orange, respectively.
Results: Monomethylated resveratrol has comparable cytoprotective effect to resveratrol, while oxyresveratrol was less potent. Trimethyl-resveratrol also decayed caspase activation, but its effect lagged behind of the parent compound. Interestingly, the dimethylated compound exhibited cytotoxic activity. Trimethylated resveratrol caused a significant mitochondrial damage, followed by a considerable generation of peroxide and superoxide, while the other analogues tend to be antioxidant. Oxyresveratrol was the only compound that did not increase the number of acidic vacuoles and did not induce autophagy.
Conclusion: Our results revealed a structure dependence in the caspase activation preventing effect of resveratrol analogues. Based on their different effect on mitochondrial membrane depolarization, free radical production and autophagy, we can hypothesize that simultaneous induction of mitochondrial damage and the elimination of reactive oxygen species are essential in keeping intracellular stress in the range that activates protective machinery, while too strong antioxidant effect might result in a failure in inducing cytoprotective mechanisms, such as autophagy.
Funding: Our project was funded by Semmelweis 250+ Excellence PhD Scholarship (EFOP-3.6.3-VEKOP-16-2017-00009).
Semmelweis University, Doctoral School of Pharmaceutical Sciences