TY - JOUR
T1 - Iron deficiency-induced loss of skeletal muscle mitochondrial proteins and respiratory capacity; the role of mitophagy and secretion of mitochondria-containing vesicles
AU - Leermakers, Pieter A.
AU - Remels, Alexander H. V.
AU - Zonneveld, Marijke I.
AU - Rouschop, Kasper M. A.
AU - Schols, Annemie M. W. J.
AU - Gosker, Harry R.
N1 - Funding Information:
We would like to thank the Microscopy Core Lab of M4I of the University of Maastricht for the scientific and technological support in the microscopy work.
Publisher Copyright:
© 2020 The Authors. The FASEB Journal published by Wiley Periodicals, Inc. on behalf of Federation of American Societies for Experimental Biology.
PY - 2020/5
Y1 - 2020/5
N2 - Iron homeostasis is essential for mitochondrial function, and iron deficiency has been associated with skeletal muscle weakness and decreased exercise capacity in patients with different chronic disorders. We hypothesized that iron deficiency-induced loss of skeletal muscle mitochondria is caused by increased mitochondrial clearance. To study this, C2C12 myotubes were subjected to the iron chelator deferiprone. Mitochondrial parameters and key constituents of mitophagy pathways were studied in presence or absence of pharmacological autophagy inhibition or knockdown of mitophagy-related proteins. Furthermore, it was explored if mitochondria were present in extracellular vesicles (EV). Iron chelation resulted in an increase in BCL2/Adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3) and BNIP3-like gene and protein levels, and the appearance of mitochondria encapsulated by lysosome-like vesicular structures in myotubes. Moreover, mitochondria were secreted via EV. These changes were associated with cellular mitochondrial impairments. These impairments were unaltered by autophagy inhibition, knockdown of mitophagy-related proteins BNIP3 and BNIP3L, or knockdown of their upstream regulator hypoxia-inducible factor 1 alpha. In conclusion, mitophagy is not essential for development of iron deficiency-induced reductions in mitochondrial proteins or respiratory capacity. The secretion of mitochondria-containing EV could present an additional pathway via which mitochondria can be cleared from iron chelation-exposed myotubes.
AB - Iron homeostasis is essential for mitochondrial function, and iron deficiency has been associated with skeletal muscle weakness and decreased exercise capacity in patients with different chronic disorders. We hypothesized that iron deficiency-induced loss of skeletal muscle mitochondria is caused by increased mitochondrial clearance. To study this, C2C12 myotubes were subjected to the iron chelator deferiprone. Mitochondrial parameters and key constituents of mitophagy pathways were studied in presence or absence of pharmacological autophagy inhibition or knockdown of mitophagy-related proteins. Furthermore, it was explored if mitochondria were present in extracellular vesicles (EV). Iron chelation resulted in an increase in BCL2/Adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3) and BNIP3-like gene and protein levels, and the appearance of mitochondria encapsulated by lysosome-like vesicular structures in myotubes. Moreover, mitochondria were secreted via EV. These changes were associated with cellular mitochondrial impairments. These impairments were unaltered by autophagy inhibition, knockdown of mitophagy-related proteins BNIP3 and BNIP3L, or knockdown of their upstream regulator hypoxia-inducible factor 1 alpha. In conclusion, mitophagy is not essential for development of iron deficiency-induced reductions in mitochondrial proteins or respiratory capacity. The secretion of mitochondria-containing EV could present an additional pathway via which mitochondria can be cleared from iron chelation-exposed myotubes.
KW - extracellular vesicles
KW - mitochondrial clearance
KW - myotubes
KW - iron depletion
KW - QUALITY-CONTROL
KW - INDUCTION
KW - AUTOPHAGY
KW - ANEMIA
KW - ENZYMES
U2 - 10.1096/fj.201901815R
DO - 10.1096/fj.201901815R
M3 - Article
C2 - 32202346
SN - 0892-6638
VL - 34
SP - 6703
EP - 6717
JO - Faseb Journal
JF - Faseb Journal
IS - 5
ER -