Format

Send to

Choose Destination
Free Radic Biol Med. 2018 Oct;126:379-392. doi: 10.1016/j.freeradbiomed.2018.08.023. Epub 2018 Aug 23.

Manganese porphyrin redox state in endothelial cells: Resonance Raman studies and implications for antioxidant protection towards peroxynitrite.

Author information

1
Departmento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Center for Free Radical and Biomedical Research, Universidad de la República, Montevideo, Uruguay.
2
Departamento de Química Inorgánica, Analítica y Química Física and INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. 2, piso 1, C1428EHA Buenos Aires, Argentina.
3
Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA.
4
Center for Free Radical and Biomedical Research, Universidad de la República, Montevideo, Uruguay; Laboratorio de Fisicoquímica Biológica, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay.
5
Departmento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Center for Free Radical and Biomedical Research, Universidad de la República, Montevideo, Uruguay. Electronic address: rradi@fmed.edu.uy.

Abstract

Cationic manganese(III) ortho N-substituted pyridylporphyrins (MnP) act as efficient antioxidants catalyzing superoxide dismutation and accelerating peroxynitrite reduction. Importantly, MnP can reach mitochondria offering protection against reactive species in different animal models of disease. Although an LC-MS/MS-based method for MnP quantitation and subcellular distribution has been reported, a direct method capable of evaluating both the uptake and the redox state of MnP in living cells has not yet been developed. In the present work we applied resonance Raman (RR) spectroscopy to analyze the intracellular accumulation of two potent MnP-based lipophilic SOD mimics, MnTnBuOE-2-PyP5+ and MnTnHex-2-PyP5+ within endothelial cells. RR experiments with isolated mitochondria revealed that the reduction of Mn(III)P was affected by inhibitors of the electron transport chain, supporting the action of MnP as efficient redox active compounds in mitochondria. Indeed, RR spectra confirmed that MnP added in the Mn(III) state can be incorporated into the cells, readily reduced by intracellular components to the Mn(II) state and oxidized by peroxynitrite. To assess the combined impact of reactivity and bioavailability, we studied the kinetics of Mn(III)TnBuOE-2-PyP5+ with peroxynitrite and evaluated the cytoprotective capacity of MnP by exposing the endothelial cells to nitro-oxidative stress induced by peroxynitrite. We observed a preservation of normal mitochondrial function, attenuation of cell damage and prevention of apoptotic cell death. These data introduce a novel application of RR spectroscopy for the direct detection of MnP and their redox states inside living cells, and helps to rationalize their antioxidant capacity in biological systems.

KEYWORDS:

Endothelial cells; Manganese porphyrin; Mitochondria; Peroxynitrite; Resonance Raman

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center