Identifying Specific Subcellular Organelle Damage by Photosensitized Oxidations

Autor(es)

Tsubone, Tayana Mazin ^{[1, 2]} ; Martins, Waleska Kerllen ^{[2, 3]} ; Baptista, Mauricio S. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Phys, Sao Paulo - Brazil

^[2] Univ Sao Paulo, Dept Biochem, Inst Chem, Sao Paulo - Brazil

^[3] Anhanguera Univ Sao Paulo, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: YALE JOURNAL OF BIOLOGY AND MEDICINE; v. 92, n. 3, p. 413-422, SEP 2019.
• Citações Web of Science: 0

Resumo

The search for conditions that maximize the outcome of Photodynamic Therapy (PDT dagger) continues. Recent data indicate that PDT-induced cell death depends more on the specific intracellular location of the photosensitizer (PS) than on any other parameter. Indeed, knowledge of the PS intracellular location allows the establishment of clear relationships between the mechanism of cell death and the PDT efficacy. In order to determine the intracellular localization sites of a given PS, classical co-localization protocols, which are based in the comparison of the emissive profiles of organelle-specific probes to those of the PS, are usually performed. Since PSs are usually not efficient fluorophores, co-localization protocols require relatively high PS concentrations (micromolar range), distorting the whole proposal of the experiment, as high PS concentration means accumulation in many low-affinity sites. To overcome this difficulty, herein we describe a method that identifies PS intracellular localization by recognizing and quantifying the photodamage at intracellular organelles. We propose that irradiation protocols and characterization of major sites of photodamage results from many cycles of photosensitized oxidations, furnishing an integrated picture of the PS location. By comparing the results of protocols based in either method, we showed that the analysis of the damaged organelles can be conducted at optimal conditions (low PS concentrations), providing clear correlations with cell death mechanisms, which is not the case for the results obtained with co-localization protocols. Experiments using PSs that target either mitochondria or lysosomes were described and investigated in detail, showing that evaluating organelle damage is as simple as performing co-localization protocols. (AU)

• Processo FAPESP: 13/16532-1 - Mecanismo da internalização fotoquímica
• Beneficiário: Tayana Mazin Tsubone
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 13/07937-8 - Redoxoma
• Beneficiário: Ohara Augusto
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs