Humanin expression in skeletal muscles of patients with chronic progressive external ophthalmoplegia.
We showed that humanin (HN), an endogenous peptide against Alzheimer disease-related insults, was expressed in muscles of patients with chronic progressive external ophthalmoplegia (CPEO), a major mitochondrial disease. Because HN was recently found to block proapoptotic Bax function and exert its versatile cytoprotective effects in association with an increase in ATP levels, HN expression may thus reflect a physiological response against degenerative changes in the muscles of patients with CPEO. We found HN expression in all four patients examined, each of whom had different mitochondrial DNA mutations including two different single DNA deletions, multiple deletions, and no major mutations detected. We also found that HN expression was not linked to focal cytochrome c deficiency, strongly associated with the subtype of CPEO with single deletions. These results suggest that HN expression is more closely related to degenerative changes in all types of CPEO. Notably, HN was also expressed in non-degenerative muscle fibers of patients with CPEO or Leigh syndrome, who had the 8993T>G mutation in the mitochondrial ATPase 6 gene known to be associated with impaired ATP synthesis. Collectively, our findings suggest that HN may be specifically expressed in response to defects in energy production in muscles with mitochondrial abnormalities.
Kin
Tesseki
T
Department of Neurology, Nara Medical University School of Medicine, 840 Shijo-cho, Kashihara, Nara 634-8522, Japan.
Sugie
Kazuma
K
Department of Neurology, Nara Medical University School of Medicine, 840 Shijo-cho, Kashihara, Nara 634-8522, Japan.
Hirano
Makito
M
Department of Neurology, Nara Medical University School of Medicine, 840 Shijo-cho, Kashihara, Nara 634-8522, Japan. hirano_makito@yahoo.co.jp.
Goto
Yu-Ichi
YI
Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.
Nishino
Ichizo
I
Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.
Ueno
Satoshi
S
Department of Neurology, Nara Medical University School of Medicine, 840 Shijo-cho, Kashihara, Nara 634-8522, Japan.
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D045304:Cytochromes c / Q000172:deficiency; D004272:DNA, Mitochondrial / Q000235:genetics; D005260:Female; D015870:Gene Expression; D006801:Humans; D007223:Infant; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D007888:Leigh Disease / Q000235:genetics / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D025261:Mitochondrial Proton-Translocating ATPases / Q000235:genetics; D018482:Muscle, Skeletal / Q000378:metabolism*; D017246:Ophthalmoplegia, Chronic Progressive External / Q000235:genetics* / Q000378:metabolism; D010086:Oxidative Phosphorylation Coupling Factors / Q000235:genetics; D017354:Point Mutation; D017384:Sequence Deletion
D004272:DNA, Mitochondrial; D047908:Intracellular Signaling Peptides and Proteins; D010086:Oxidative Phosphorylation Coupling Factors; C427211:humanin; D045304:Cytochromes c; C000628217:F(6) ATPase; D025261:Mitochondrial Proton-Translocating ATPases