Inhibition of protein kinase C βII isoform ameliorates methylglyoxal advanced glycation endproduct-induced cardiomyocyte contractile dysfunction

Life Sci. 2014 Jan 14;94(1):83-91. doi: 10.1016/j.lfs.2013.11.011. Epub 2013 Nov 21.


Aims: Accumulation of advanced glycation endproduct (AGE) contributes to diabetic complication including diabetic cardiomyopathy although the precise underlying mechanism still remains elusive. Recent evidence depicted a pivotal role of protein kinase C (PKC) in diabetic complications. To this end, this study was designed to examine if PKCβII contributes to AGE-induced cardiomyocyte contractile and intracellular Ca(2+) aberrations.

Main methods: Adult rat cardiomyocytes were incubated with methylglyoxal-AGE (MG-AGE) in the absence or presence of the PKCβII inhibitor LY333531 for 12h. Contractile and intracellular Ca(2+) properties were assessed using an IonOptix system including peak shortening (PS), maximal velocity of shortening/relengthening (±dL/dt), time-to-PS (TPS), time-to-90% relengthening (TR90), rise in intracellular Ca(2+) Fura-2 fluorescence intensity and intracellular Ca(2+) decay. Oxidative stress, O2(-) production and mitochondrial integrity were examined using TBARS, fluorescence imaging, aconitase activity and Western blotting.

Key findings: MG-AGE compromised contractile and intracellular Ca(2+) properties including reduced PS, ±dL/dt, prolonged TPS and TR90, decreased electrically stimulated rise in intracellular Ca(2+) and delayed intracellular Ca(2+) clearance, the effects of which were ablated by the PKCβII inhibitor LY333531. Inhibition of PKCβII rescued MG-AGE-induced oxidative stress, O2(-) generation, cell death, apoptosis and mitochondrial injury (reduced aconitase activity, UCP-2 and PGC-1α). In vitro studies revealed that PKCβII inhibition-induced beneficial effects were replicated by the NADPH oxidase inhibitor apocynin and were mitigated by the mitochondrial uncoupler FCCP.

Significance: These findings implicated the therapeutic potential of specific inhibition of PKCβII isoform in the management of AGE accumulation-induced myopathic anomalies.

Keywords: Advanced glycation endproduct; Cardiomyocytes; Contractile function; Protein kinase C isoform.

MeSH terms

  • Aconitate Hydratase / metabolism
  • Animals
  • Apoptosis
  • Blotting, Western
  • Calcium / metabolism
  • Glycation End Products, Advanced / metabolism*
  • Indoles / pharmacology
  • Male
  • Maleimides / pharmacology
  • Mitochondria / pathology
  • Myocardial Contraction / physiology*
  • Myocytes, Cardiac / metabolism*
  • Myocytes, Cardiac / pathology
  • Oxidative Stress
  • Protein Kinase C beta / antagonists & inhibitors*
  • Pyruvaldehyde / metabolism*
  • Rats
  • Rats, Sprague-Dawley


  • Glycation End Products, Advanced
  • Indoles
  • Maleimides
  • ruboxistaurin
  • Pyruvaldehyde
  • Protein Kinase C beta
  • Aconitate Hydratase
  • Calcium