The protective role of protein L-isoaspartyl (D-aspartate) O-methyltransferase for maintenance of mitochondrial morphology in A549 cell.
The increasing amounts of evidence with abnormal aging process have been involved in the pathogenesis of chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF). Mice with deficient protein L-isoaspartate (D-aspartate) O-methyl transferase 1 (PCMT1) expression reveal acceleration of aging and result in the increased proportion of D-aspartate (D-Asp) residues and dysfunction in proteins. Furthermore, mitochondrial morphology and functions are associated with COPD and IPF pathogenesis. The purpose of the current study was to investigate the role of PCMT1 on mitochondrial morphology using A549 cells.



We investigated PCMT1, prohibitin1 (PHB1), mitochondrial membrane proteins expression, mitochondrial morphology, and the proportion of D-Asp residues in PHB1 in A549 cells with (PCMT1-KD) and without the context of decreased PCMT1 expression (PCMT1-Cont) using electron microscopy, fluorescence staining, Western blot analysis, and the ATP content per cells. To investigate the effects of the PCMT1-KD cells, we developed double-transfected cell lines containing either the cytosolic or the endoplasmic isoform of PCMT1.



We found a significantly higher proportion of D-Asp residues in PHB1 in PCMT1-KD cells than that in PCMT1-Cont cells. The PCMT1-KD cells without cigarette smoke extract exposure were characterized by a significantly increased proportion of the D-Asp residues in PHB1, damaged mitochondrial ultrastructure, and a tendency toward the fission direction of the mitochondrial dynamics followed by a significant decrease in the cellular ATP content.



The increased proportion of the D-Asp residues may contribute to COPD pathogenesis, via irreversible protein conformational changes, followed by mitochondrial dysfunction.
a Department of Pharmacology , Ehime University Graduate School of Medicine , Toon City , Japan.
Masahito
M
Ogasawara
b Laboratory of Molecular Cell Biology , Department of Life Sciences Pharmacy , School of Pharmaceutical Sciences, Kobe Gakuin University , Chuo-ku, Kobe City , Japan.
Mieko
M
Otani
b Laboratory of Molecular Cell Biology , Department of Life Sciences Pharmacy , School of Pharmaceutical Sciences, Kobe Gakuin University , Chuo-ku, Kobe City , Japan.
Masaoki
M
Takano
c Integrated Center for Science , Shigenobu Station, Ehime University Graduate School of Medicine , Toon City , Japan.
Masachika
M
Shudou
d Department of Environment Health , National Institute of Public Health , Minami, Wako City , Saitama , Japan.
Yohei
Y
Inaba
e Biological Resources and Post-Harvest Division , Japan International Research Center for Agricultural Sciences , Tsukuba City , Ibaraki , Japan.
Satoru
S
Nirasawa
f Akita Research Institute of Food and Brewing , Akita City , Japan.
Saori
S
Takahashi
c Integrated Center for Science , Shigenobu Station, Ehime University Graduate School of Medicine , Toon City , Japan.
Takeshi
T
Kiyoi
c Integrated Center for Science , Shigenobu Station, Ehime University Graduate School of Medicine , Toon City , Japan.
Yuki
Y
Tanaka
c Integrated Center for Science , Shigenobu Station, Ehime University Graduate School of Medicine , Toon City , Japan.
Kenji
K
Kameda
d Department of Environment Health , National Institute of Public Health , Minami, Wako City , Saitama , Japan.
Naoki
N
Kunugita
a Department of Pharmacology , Ehime University Graduate School of Medicine , Toon City , Japan.
Kazutaka
K
Maeyama
b Laboratory of Molecular Cell Biology , Department of Life Sciences Pharmacy , School of Pharmaceutical Sciences, Kobe Gakuin University , Chuo-ku, Kobe City , Japan.
Keiji
K
Sano
g Department of Respiratory Medicine , Iwate Medical University School of Medicine , Morioka City , Japan.
Masahiro
M
Yamashita
g Department of Respiratory Medicine , Iwate Medical University School of Medicine , Morioka City , Japan.
Kohei
K
Yamauchi
D000072283:A549 Cells; D000255:Adenosine Triphosphate / Q000378:metabolism; D059865:Endoplasmic Reticulum Stress; D006801:Humans; D008928:Mitochondria / Q000201:enzymology* / Q000648:ultrastructure; D063154:Mitochondrial Dynamics; D018384:Oxidative Stress; D000091402:Prohibitins; D026601:Protein D-Aspartate-L-Isoaspartate Methyltransferase / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism*
C000717328:PHB protein, human; D000091402:Prohibitins; D012097:Repressor Proteins; D000255:Adenosine Triphosphate; D026601:Protein D-Aspartate-L-Isoaspartate Methyltransferase
d-aspartic acid residue; isomerization; protein damage