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Fluctuating Weak Magnetic Fields Induce Marked Mitophagy
Author(s) -
Toda Takuro,
Ito Mikako,
Mori Kaneo,
Ohno Kinji
Publication year - 2020
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2020.34.s1.03782
Subject(s) - mitophagy , mitochondrion , microbiology and biotechnology , chemistry , pink1 , biophysics , biochemistry , biology , apoptosis , autophagy
Previous epidemiological studies have revealed that occupational exposure to extremely low frequency weak magnetic fields (ELF‐WMF) is associated with the development of neurodegenerative diseases including Alzheimer’s disease (AD) and amyotrophic lateral sclerosis (ALS). The molecular mechanism of these detrimental effects, however, remain mostly unelucidated. We examined the effects of extremely low frequency fluctuation of weak magnetic fields (ELF‐WMF) on cultured mammalian cells. While applying ELF‐WMF, we examined the temporal profiles of expression levels of VDAC1, a mitochondrial outer membrane protein, and seven electron transport complex (ETC) proteins of NDUFS1 (ETC I), NDUFB8 (ETC I), SDHB (ETC II), UQCRFS1 (ETC III), UQCRC2 (ETC III), MTCOI (ETC IV), and ATP5A (ETC V). ELF‐WMF downregulated the amounts of these proteins at 3 h and recovered them at 12 h. Quantification of the amount of mitochondria with MitoTracker Green showed that the mitochondrial mass was decreased to 70% at 3 h and recovered at 12 h. In addition, mitophagy‐related proteins of PINK1 and LC3‐II were increased by ELF‐WMF at 1.5–2.5 h. Quantification of ETC enzymatic activities in protein homogenates revealed that ELF‐WMF exclusively suppressed the activity of ETC II in 10 min. We report that ELF‐WMF much weaker than geomagnetic fields suppresses the enzymatic activity of ETC II, and provokes mitophagy. Mitophagy is a cellular quality‐assurance system to eliminate damaged mitochondria. Mitophagy induced by ELF‐WMF may be causally associated with the development and progression of AD and ALS. Contrarily, ELF‐WMF finely tuned to preferentially eliminate damaged mitochondria may be able to ameliorate Parkinson’s disease, in which compromised mitophagy is a cause of the disease. Support or Funding Information This research was supported by grants‐in‐aids from MEXT, MHLW, and AMED of Japan.