Comparison of light-induced formation of reactive oxygen species and the membrane destruction of two mesoporphyrin derivatives in liposomes

Barnabás Bőcskei-Antal,Ádám Zolcsák,István Voszka,Nikoletta Kósa,Katalin Tóth,Levente Herenyi,Gabriella Csík

doi:10.1038/s41598-019-47841-x

Barnabás Bőcskei-Antal, Ádám Zolcsák + Show 5 more

Open Access

https://doi.org/10.1038/s41598-019-47841-x

Copy DOI

Journal: Scientific Reports	Publication Date: Aug 5, 2019
Citations: 8	License type: open-access

Affiliation: Semmelweis University, Heidelberg University

Abstract

The photodynamic effect requires the simultaneous presence of light, photosensitizer (PS) and molecular oxygen. In this process, the photoinduced damage of cells is caused by reactive oxygen species (ROS). Besides DNA, the other target of ROS is the membranes, separating internal compartments in living cells. Hence, the ability of ROS formation of porphyrins as PSs, in liposomes as simple models of cellular membranes is of outstanding interest. Earlier we compared the binding parameters and locations of mesoporphyrin IX dihydrochloride (MPCl) and mesoporphyrin IX dimethyl ester (MPE), in small unilamellar vesicles (SUV) made from various saturated phosphatidylcholines. In this study, we used the same kinds of samples for comparing the ROS forming ability. Triiodide production from potassium iodide because of light-induced ROS in the presence of molybdate catalyst was applied, and the amount of product was quantitatively followed by optical spectrometry. Furthermore, we demonstrated and carefully studied SUVs disruption as direct evidence of membrane destruction by the methods of dynamic light scattering (DLS) and fluorescence correlation spectroscopy (FCS), applying unsaturated phosphatidylcholines as membrane components. Although the ROS forming ability is more pronounced in the case of MPCl, we found that the measured disruption was more effective in the samples containing MPE.

Highlights

Photodynamic therapy (PDT) is a form of phototherapy, which involves a dye with negligible dark toxicity called the photosensitizer (PS), the appropriate wavelength light to excite the PS, and tissue oxygen to elicit the death of the desired cells
The photochemical mechanism, which lies in the background of PDT, is that a PS is excited by a specific wavelength light and the excited triplet state of the PS can interact with the ground state oxygen (3Σg) in the tissue or with other substrates forming singlet oxygen (1Δg) and other reactive oxygen species (ROS)
Earlier in the course of our research, we determined the assumable location of two different porphyrin PSs, namely mesoporphyrin IX dihydrochloride (MPCl) and mesoporphyrin IX dimethyl ester (MPE), in liposomes as simple models of cellular membranes by fluorescence line narrowing spectroscopy

Summary

Introduction

Photodynamic therapy (PDT) is a form of phototherapy, which involves a dye with negligible dark toxicity called the photosensitizer (PS), the appropriate wavelength light to excite the PS, and tissue oxygen to elicit the death of the desired cells. Most of the PSs are located in the membranes, and they can have significant differences, depending on their binding site in the membrane; since the deeper the PS is located, the more accessible it is to the 3–4 times higher oxygen concentration in the membranes compared to the cytosol. Another crucial question is the structure and lipid composition of membranes. We compared the binding parameters of these porphyrins in the same SUVs15,16

Methods

Results

Conclusion