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

Abstract

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. SIGNIFICANCE: Hyperglycemia is the main physiological condition that provokes tissue and vascular injuries in heart of diabetic patients. However, the changings at large scale in the expression of proteins of cardiomyocytes generated by this condition was not yet studied. Here we report for the first time the altered biosynthesis of nine groups of proteins of H9c2 cells activated by high glucose concentrations and by cardiotonic steroids (CTS). Furthermore, the increased biosynthesis of Eifs, Eefs and 14-3-3 protein groups by CTS, which play a crucial role in cardiomyopathies are original data reported in this work. These findings not only enhance our knowledge concerning to the effects of hyperglycemia and CTS on H9c2 cells but also indicate potential molecular targets to interfere in diabetes cardiomyopathy progression.