Regulation of mitochondrial morphology and function by O-GlcNAcylation in neonatal cardiac myocytes

Ayako Makino, Jorge Suarez, Thomas Gawlowski, Wenlong Han, Hong Wang, Brian T. Scott, Wolfgang H. Dillmann

Research output: Contribution to journalArticlepeer-review

62 Scopus citations


Mitochondria are crucial organelles in cell life serving as a source of energy production and as regulators of Ca2+ homeostasis, apoptosis, and development. Mitochondria frequently change their shape by fusion and fission, and recent research on these morphological dynamics of mitochondria has highlighted their role in normal cell physiology and disease. In this study, we investigated the effect of high glucose on mitochondrial dynamics in neonatal cardiac myocytes (NCMs). High-glucose treatment of NCMs significantly decreased the level of optical atrophy 1 (OPA1) (mitochondrial fusion-related protein) protein expression. NCMs exhibit two different kinds of mitochondrial structure: round shape around the nuclear area and elongated tubular structures in the pseudopod area. High-glucose-treated NCMs exhibited augmented mitochondrial fragmentation in the pseudopod area. This effect was significantly decreased by OPA1 overexpression. High-glucose exposure also led to increased O-GlcNAcylation of OPA1 in NCMs. GlcNAcase (GCA) overexpression in high-glucose-treated NCMs decreased OPA1 protein O-GlcNAcylation and significantly increased mitochondrial elongation. In addition to the morphological change caused by high glucose, we observed that high glucose decreased mitochondrial membrane potential and complex IV activity and that OPA1 overexpression increased both levels to the control level. These data suggest that decreased OPA1 protein level and increased O-GlcNAcylation of OPA1 protein by high glucose lead to mitochondrial dysfunction by increasing mitochondrial fragmentation, decreasing mitochondrial membrane potential, and attenuating the activity of mitochondrial complex IV, and that overexpression of OPA1 and GCA in cardiac myocytes may help improve the cardiac dysfunction in diabetes.

Original languageEnglish (US)
Pages (from-to)1296-1302
Number of pages7
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Issue number6
StatePublished - Jun 2011
Externally publishedYes


  • Glcnacase
  • Hyperglycemia
  • Membrane potential
  • Mitochondrial dynamics
  • Mitochondrial fission and fusion

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


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