Proteomic profiling reveals comprehensive insights into adrenergic receptor-mediated hypertrophy in neonatal rat cardiomyocytes

Analysis of the Serum Peptidomics Profile for Cats With Sarcomeric Gene Mutation and Hypertrophic Cardiomyopathy

Background: Hypertrophic cardiomyopathy (HCM) has a complex phenotype that is partly explained by genetic variants related to this disease. The serum peptidome profile is a promising approach to define clinically relevant biomarkers. This study aimed to classify peptide patterns in serum samples between cats with sarcomeric gene mutations and normal cats.

Materials and Methods: In the total serum samples from 31 cats, several essential proteins were identified by peptidomics analysis. The 5,946 peptides were differentially expressed in cats with sarcomeric gene mutations compared with cats without mutations.

Results: Our results demonstrated characteristic protein expression in control cats, Maine Coon cats, and Maine Coon cats with gene mutations. In cats with gene mutations, peptide expression profiling showed an association with three peptides, Cytochrome 3a132 (CYP3A132), forkhead box O1 (FOXO1), and ArfGAP, with GTPase domains, ankyrin repeats, and PH domain 2 (AGAP2).

Discussion: The serum peptidome of cats with mutations might provide supporting evidence for the dysregulation of metabolic and structural proteins. Genetic and peptidomics investigations may help elucidate the phenotypic variability of HCM and treatment targets to reduce morbidity and mortality of HCM in cats.

Comparative proteomics analysis of differential proteins in respond to doxorubicin resistance in myelogenous leukemia cell lines

Background

Chemoresistance remains a significant challenge in chronic myelogenous leukemia (CML) management, which is one of the most critical prognostic factors. Elucidation the molecular mechanisms underlying the resistance to chemoresistance may lead to better clinical outcomes.

Results

In order to identify potential protein targets involved in the drug-resistant phenotype of leukemia, especially the chronic myelogenous leukemia (CML), we used a high-resolution “ultra-zoom” 2DE-based proteomics approach to characterize global protein expression patterns in doxorubicin-resistant myelogenous leukemia cells compared with parental control cells. Ultra-high resolution of 2DE was achieved by using a series of slightly overlapping narrow-range IPG strips during isoelectric focusing (IEF) separation. A total number of 44 proteins with altered abundances were detected and identified by MALDI-TOF or LC-MS/MS. Among these proteins, enolase, aldolase, HSP70 and sorcin were up-regulated in doxorubicin-resistant myelogenous leukemia cell line, whereas HSP27 was down-regulated. Some of the results have been validated by Western blotting. Both enolase and aldolase were first reported to be involved in chemoresistance, suggesting that process of glycolysis in doxorubicin-resistant myelogenous leukemia cells was accelerated to some extent to provide more energy to survive chemical stress. Possible roles of most of the identified proteins in development of chemoresistance in myelogenous leukemia cells were fully discussed. The results presented here could provide clues to further study for elucidating the mechanisms underlying drug resistance in leukemia.

Conclusions

As a whole, under the chemical stress, the doxorubicin-resistant myelogenous leukemia cells may employ various protective strategies to survive. These include: (i) pumping the cytotoxic drug out of the cells by P-glycoprotein, (ii) increased storage of fermentable fuel, (iii) sophisticated cellular protection by molecular chaperones, (iv) improved handling of intracellular calcium, (v) increased glucose utilization via increased rates of glycolysis. In the present study, proteomic analysis of leukemia cells and their drug resistant variants revealed multiple alterations in protein expression. Our results indicate that the development of drug resistance in doxorubicin-resistant myelogenous leukemia cells is a complex phenomenon undergoing several mechanisms.

Electronic supplementary material

The online version of this article (doi:10.1186/s12953-014-0057-y) contains supplementary material, which is available to authorized users.

Heat shock protein 70 acts as a potential biomarker for early diagnosis of heart failure

Early identification for heart failure (HF) may be useful for disease modifying treatment in order to reduce heart disease progression or even to reverse it. In our previous studies, we have revealed a group of heat shock proteins (HSPs) which might be related to neonatal rat cardiomyocyte hypertrophy by proteomic approach. Here, we confirm that HSPs, including HSP27 and HSP70, altered in the early stage of cardiac remodeling in vivo animal model. Furthermore, plasma concentrations of those HSPs and their potential screening value were evaluated at different stages in 222 patient subjects. Plasma HSP27, HSP70 and HSP90 were measured using enzyme-linked immunosorbent assay. Results indicate that HSP70 was positively correlated to the severity (progression) of HF (r = 0.456, p<0.001). The area under the rate of change (ROC) curve was 0.601 (p = 0.017) in patients with stage B HF and 0.835 (p<0.001) in those with stage C HF. However, HSP27 and HSP90 did not display significant changes in any stage of HF in this study. Taken together, plasma concentrations of HSP70 elevated with the progression of HF and might act as a potential screening biomarker for early diagnosis of HF.

Identification of proteins responding to adrenergic receptor subtype-specific hypertrophy in cardiomyocytes by proteomic approaches

The individual signaling pathways underlying cardiac hypertrophy, which is induced by either α or β adrenergic receptor (AR), are different. Activation of different AR subtypes couples to different G proteins and induction of specific signaling pathways, which ultimately results in subtype-specific regulation of cardiac function. We present the first proteomics study identifying proteins that are related to AR subtype-specific hypertrophy in cardiomyocytes by comparing the two-dimensional electrophoresis patterns between neonatal rat cardiomyocytes treated by phenylepinephrin (PE) and by isoproterenol (ISO). An improved 2-DE strategy was used in these comparative experiments. Twenty-five differentially expressed proteins in cardiomyocytes treated by PE or treated by ISO were successfully analyzed and identified using matrix-assisted laser desorption/ionization-time of flight mass spectrometry, especially those that might be responsible to intracellular oxidative stress such as dismutase, peroxiredoxin, and thioredoxin-like protein p46. In addition, induced reactive oxygen species were also found to be AR subtype-specifically relevant to endoplasmic reticulum proteinase ERK1/2 phosphorylation during the development of hypertrophy induced by different AR subtypes. The results will help to better understand the underlying mechanisms of different adrenergic receptor subtype-induced hypertrophy.

Investigating the secretome: lessons about the cells that comprise the heart

The cell/environment interface is composed of the proteins of plasma membrane which face the extracellular space and by the proteins secreted directly by the cell of origin or by neighboring cells. The secreted proteins can act as extracellular matrix proteins and/or autocrine/paracrine proteins. This report discusses the technical aspects involved in the identification and characterization of the secreted proteins of specific cell types that comprise the heart. These aspects include the culturing of the cells, cell co-culturing and quantitative labeling, conditioned media collection and dealing with high abundant serum proteins, post-translational modification enrichment, the use of protein separation methods and mass spectrometry, protein identification and validation and the incorporation of pathway analysis to better understand the novel discovery on the background of already known experimental biological systems. The proteomic methods have the solid emplacement in cardiovascular research and the identification of proteins secreted by cardiac cells has been used in various applications such as determination the specificity between secretomes of different cell types, e.g. cardiac stem cells and cardiac myocytes, for the global secretome screening of e.g. human arterial smooth muscle cells, for the mapping of the beneficial effect of conditioned medium of one cell type on the other cell type, e.g. conditioned medium of human mesenchymal stem cells on cardiac myocytes, and for the searching the candidate paracrine factors and potential biomarkers.