Quantitative proteomic analysis reveals high interference on protein expression of H9c2 cells activated with glucose and cardiotonic steroids.

In recent decades, the incidence of death and morbidity due to diabetes has increased worldwide, causing a high social and economic impact. Diabetes is a major cause of blindness, kidney failure, heart attack, stroke and lower limb amputation. However, the molecular mechanisms that make the heart and kidneys the main targets of diabetes are not completely understood. To better understand the complex biochemical mechanism of diabetic cardiomyopathy, we investigated the effects of hyperglycemia with concomitant digoxin and ouabain stimulation in H9c2 cells. Total extracted proteins were analyzed by label-free LC-MS/MS, quantified by Scaffold software and validated by parallel reaction monitoring (PRM) methodology. Here, we show that the eukaryotic initiation factors (Eifs) and elongation factors (Eefs) Eif3f, Eef2 and Eif4a1 are overexpressed following cardiotonic steroid (CTS) stimulation. Similarly, the expression of four 14-3-3 proteins that play a key role in cardiac ventricular compaction was altered after CTS stimulation. In total, the expression of nine protein groups was altered in response to the stimulation of H9c2 cells. Here, the biological consequences of these changes are discussed in depth.