Photo-Oxidation of Unilamellar Vesicles by a Lipophilic Pterin: Deciphering Biomembrane Photodamage

Autor(es)

Vignoni, Mariana ^[1] ; Noel Urrutia, Maria ^[1] ; Junqueira, Helena C. ^[2] ; Greer, Alexander ^{[3, 4]} ; Reis, Ana ^[5] ; Baptista, Mauricio S. ^[2] ; Itri, Rosangela ^[6] ; Thomas, Andres H. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Nacl La Plata, CONICET, Inst Invest Fisicoquim Teor & Aplicadas, Dept Quim, Fac Cs Exactas, CCT La Plata, CC 16, Suc 4, RA-1900 La Plata, Buenos Aires - Argentina

^[2] Univ Sao Paulo, Inst Quim, Dept Bioquim, BR-05508000 Sao Paulo - Brazil

^[3] CUNY Brooklyn Coll, Dept Chem, Brooklyn, NY 11210 - USA

^[4] CUNY, Grad Ctr, PhD Program Chem, 365 Fifth Ave, New York, NY 10016 - USA

^[5] Univ Porto, Fac Sci, Dept Chem & Biochem, ICETA, REQUIMTE, LAQV, P-4169007 Porto - Portugal

^[6] Univ Sao Paulo, Inst Phys, BR-05508090 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Langmuir; v. 34, n. 50, p. 15578-15586, DEC 18 2018.
• Citações Web of Science: 0

Resumo

Pterins are natural products that can photosensitize the oxidation of DNA, proteins, and phospholipids. Recently, a new series of decyl-chain (i.e., lipophilic) pterins were synthesized and their photophysical properties were investigated. These decyl-pterins led to efficient intercalation in large unilamellar vesicles and produced, under UVA irradiation, singlet molecular oxygen, a highly oxidative species that react with polyunsaturated fatty acids (PUFAs) to form hydroperoxides. Here, we demonstrate that the association of 4-(decyloxy)pteridin-2-amine (O-decyl-Ptr) to lipid membranes is key to its ability to trigger phospholipid oxidation in unilamellar vesicles of phosphatidylcholine rich in PUFAs used as model biomembranes. Our results show that O-decyl-Ptr is at least 1 order of magnitude more efficient photosensitizer of lipids than pterin (Ptr), the unsubstituted derivative of the pterin family, which is more hydrophilic and freely passes across lipid membranes. Lipid peroxidation photosensitized by O-decyl-Ptr was detected by the formation of conjugated dienes and oxidized lipids, such as hydroxy and hydroperoxide derivatives. These primary products undergo a rapid conversion into short-chain secondary products by cleavage of the fatty-acid chains, some of which are due to subsequent photosensitized reactions. As a consequence, a fast increase in membrane permeability is observed. Therefore, lipid oxidation induced by O-decyl-Ptr could promote cell photodamage due to the biomembrane integrity loss, which in turn may trigger cell death. (AU)

• Processo FAPESP: 13/07937-8 - Redoxoma
• Beneficiário: Ohara Augusto
• Linha de fomento: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 16/04296-0 - Fotossensibilização e fotodano de células e modelos biomiméticos por derivados pterin
• Beneficiário: Mauricio da Silva Baptista
• Linha de fomento: Auxílio à Pesquisa - Pesquisador Visitante - Internacional
• Processo FAPESP: 12/50680-5 - Fotossensibilização nas ciências da vida
• Beneficiário: Mauricio da Silva Baptista
• Linha de fomento: Auxílio à Pesquisa - Temático