Impact of Silibinin A on Bioenergetics in PC12APPsw Cells and Mitochondrial Membrane Properties in Murine Brain Mitochondria

Carsten Esselun; Bastian Bruns; Stephanie Hagl; Rekha Grewal; Gunter P Eckert

doi:10.3390/antiox10101520

Impact of Silibinin A on Bioenergetics in PC12APP_sw Cells and Mitochondrial Membrane Properties in Murine Brain Mitochondria

Antioxidants (Basel). 2021 Sep 24;10(10):1520. doi: 10.3390/antiox10101520.

Authors

Carsten Esselun¹, Bastian Bruns², Stephanie Hagl², Rekha Grewal¹, Gunter P Eckert¹

Affiliations

¹ Institute for Nutritional Sciences, Justus-Liebig-University of Giessen, 35392 Giessen, Germany.
² Institute of Pharmacology, Goethe-University of Frankfurt am Main, 60439 Frankfurt am Main, Germany.

Abstract

Age-related multifactorial diseases, such as the neurodegenerative Alzheimer's disease (AD), still remain a challenge to today's society. One mechanism associated with AD and aging in general is mitochondrial dysfunction (MD). Increasing MD is suggested to trigger other pathological processes commonly associated with neurodegenerative diseases. Silibinin A (SIL) is the main bioactive compound of the Silymarin extract from the Mediterranean plant Silybum marianum (L.) (GAERTN/Compositae). It is readily available as a herbal drug and well established in the treatment of liver diseases as a potent radical scavenger reducing lipid peroxidation and stabilize membrane properties. Recent data suggest that SIL might also act on neurological changes related to MD. PC12APP_sw cells produce low levels of human Aβ and thus act as a cellular model of early AD showing changed mitochondrial function. We investigated whether SIL could affect mitochondrial function by measuring ATP, MMP, as well as respiration, mitochondrial mass, cellular ROS and lactate/pyruvate concentrations. Furthermore, we investigated its effects on the mitochondrial membrane parameters of swelling and fluidity in mitochondria isolated from the brains of mice. In PC12APP_sw cells, SIL exhibits strong protective effects by rescuing MMP and ATP levels from SNP-induced mitochondrial damage and improving basal ATP levels. However, SIL did not affect mitochondrial respiration and mitochondrial content. SIL significantly reduced cellular ROS and pyruvate concentrations. Incubation of murine brain mitochondria with SIL significantly reduces Ca²⁺ induced swelling and improves membrane fluidity. Although OXPHOS activity was unaffected at this early stage of a developing mitochondrial dysfunction, SIL showed protective effects on MMP, ATP- after SNP-insult and ROS-levels in APPsw-transfected PC12 cells. Results from experiments with isolated mitochondria imply that positive effects possibly result from an interaction of SIL with mitochondrial membranes and/or its antioxidant activity. Thus, SIL might be a promising compound to improve cellular health when changes to mitochondrial function occur.

Keywords: NMRI; PC12APPsw; SNP; aging; flavolignan; fluidity; mitochondria; silibinin; silybin; swelling.