Akademik Veri Yönetim Sistemi
Jubilee Scientific Conference "Medicine of the Future" - 29-31 October 2020 on the occasion of the 75th Anniversary of Medical University of Plovdiv, 29 - 31 Ekim 2020, cilt.62, ss.19-20
The Role of Autophagy and Mitochondrial Dynamics in Neurodegenerative
Diseases: A Study in an Alzheimer Disease Model
Beki Kan1, Begum Bilge1, Suleyman
Bozkurt1,
Ismail Hakki Ulus2
and Devrim Oz-Arslan1*
Acibadem Mehmet Ali Aydinlar
University, School of Medicine, Departments of 1Biophysics and2 Medical Pharmacology,
Istanbul, Turkey
*Corresponding
author
Autophagy is an
essential, highly conserved intracellular pathway involved in preserving cellular
homeostasis by degradation of proteins, lipids, and organelles. Under normal
conditions, autophagy occurs at basal levels, but it is induced by several
stress conditions, including nutrient starvation, damaged organelles,
aggregated proteins, DNA damage and infection.
Cytidine-5'-diphosphocholine
(CDP-Ch), an intermediate in the biosynthesis of membrane phospholipids, is
known to have neuroprotective effects in several diseases but the underlying
precise mechanism remains elusive. The fact that choline is also involved in
programmed cell death and apoptosis suggests that its protective actions may be
associated with autophagy.
Recent studies
suggest that autophagy may have a crucial role in Alzheimer’s disease (AD). Phosphatidylcholine
(PC), one of the essential membrane components synthesized by cytidine
5’-diphosphocholine, may play a role in the formation of autophagic vesicle
membranes. In this study, we aimed to understand the effect of CDP-Ch treatment
on autophagy and mitochondrial dynamics during amyloid-beta (Aβ1-42)
mediated neuronal injury.
To this end, nerve growth factor (NGF)-differentiated
PC12 cells were treated with Aβ1-42 in the presence and absence of CDP-Ch. We examined
the levels of several autophagic markers, including LC3B, p62, Beclin-1 and
also Mitofusin-2 (Mfn-2), an outer mitochondrial membrane GTPase involved in mitochondrial
fusion by immunoblotting. Mitochondrial membrane potential (MMP) and
mitochondrial mass were evaluated by flow cytometry and confocal imaging after
probing with mitochondria-specific dyes. Oxygen consumption rate (OCR) was
measured using Agilent Seahorse XFP Cell Mito Stress Kit.
We observed
increases in LC3B and Mfn-2 levels of NGF-differentiated PC12 cells upon CDP-Ch
treatment. Aβ1-42 treatment of NGF-differentiated cells resulted in
increased levels of autophagic markers, LC3B and Beclin-1. Beta-amyloid injury changed
mitochondrial membrane potential and MitoSOX levels. CDP-Ch pre-treatment of
injured cells reduced MitoSox levels. The increases observed in Mfn-2 and
mitochondrial mass of untreated cells suggested that CDP-Ch may be involved in
mitochondrial dynamics.
Our data indicate
that CDP-Ch treatment and amyloid beta injury affect autophagy and
mitochondrial function in NGF-differentiated PC12 cells and that CDP-Ch may
elicit different effects depending on the degree of damage in the cell. An
understanding of the role of CDP- Ch in autophagy and mitochondrial dynamics
may shed light into its neuroprotective effects.
This work is supported by The Scientific and
Technological Research Council of Turkey (Grant number:114Z494).