Directory
Mauricio Baptista
| When |
Nov 19, 2024 à 10:30 AM |
|---|---|
| Where |
Salle André Collet |
| Contact |
Carlos Marques |
Photosensitized oxidations in the intracellular domain show the routes to improve photomedicine and sun protection
Oxidative damage in the membranes of specific intracellular organelles is highly correlated with the efficiency of photo-induced cell death, which is the key step for the success of photodynamic therapy (PDT). Nanoparticles of different nature can affect the intracellular delivery and the final efficiency of PDT. Processes depending on direct-contact reactions between photosensitizers and lipids are essential for the formation of lipid peroxides and subsequently of alkyl aldehydes, which cause membrane leakage and propagate the cellular damage from the initial oxidation sites. Besides the formation of transmembrane pores, lipid aldehydes have key roles as redox signaling molecules and can also dysregulate autophagy. Upon sun exposure, electrophiles that accumulate in skin cells induce the formation of lipofuscin and of several oxidation-end products, which increases substantially the sensitivity of skin cells to visible light. Strategies for the development of improved sun protection agents and PDT photosensitizers will be discussed.