Diabetologie und Stoffwechsel 2013; 18 - P289
DOI: 10.1055/s-0033-1347766

Therapeutic application of activated Protein C epigenetically constrains the redox-enzyme p66shc in diabetic nephropathy

F Bock 1, 2, K Shahzad 1, H Wang 1, R Ritzel 2, V Schwenger 3, T Madhusudhan 1, C Esmon 4, P Nawroth 2, B Isermann 1
  • 1Universitätsklinikum Magdeburg, Institut für Klinische Chemie und Pathobiochemie, Magdeburg, Germany
  • 2Universitätsklinikum Heidelberg, Innere Medizin 1 und Klinische Chemie, Heidelberg, Germany
  • 3Universitätsklinikum Heidelberg, Nierenzentrum, Heidelberg, Germany
  • 4Oklahoma Medical Reserach Foundation, Howard Hughes Medical Institute, Oklahoma City, United States

Introduction: Mice with genetically increased levels of activated Protein C (aPC) are protected against diabetic nephropathy and have decreased glomerular expression levels of the mitochondrial-targeted redox enzyme p66shc. In mice therapeutic application of aPC ameliorates indices of diabetic nephropathy and podocyte damage. The therapeutic mechanism and how intermittent application of a plasma protein with a half life of ˜25 min modifies nephropathy remain unknown.

Methods: Unilaterally nephrectomized WT mice were STZ-injected. After 4 weeks of diabetes a subgroup was i.p.-injected every other day for 4 weeks with 1 mg/kg aPC (Elli Lilly, Xigris®) or with aPC preincubated with an antibody (HAPC1573) to block its anticoagulant function. In parallel a subgroup of aPC-injected mice were orally treated with sodium butyrate for 4 weeks. In vitro immortalized murine Podocytes were treated with 2nM aPC and methylation-specific PCR (MSP) and ChIP were applied to analyze promoter methylation and acetylation of p66shc.

Results: Exogenous application of aPC and aPC-HAPC1573 ameliorates indices of diabetic nephropathy in diabetic wild-type mice. Glomerular accumulation of oxidative stress markers and of p66shc are reversed in aPC-treated diabetic mice. Renal Histone H3 acetylation and p66shc expression was increased upon diabetes and reversed with aPC-treatment. The histone H3 hyperacetylating agent sodium butyrate reversed the suppression of p66shc by aPC and abolished the beneficial effects of aPC. In vitro aPC reversed the glucose induced increase of the H3-acetyltransferase GCN5 and the hypomethylation and H3-hyperacetylation of the p66shc-promoter, which was abolished with sodium butyrate treatment.

Conclusion: Therapeutic application of aPC epigenetically suppresses the red-ox enzyme p66shc and through this indirect mechanism aPC has antioxidative and cytoprotective properties that are independent of its anticoagulant function.