Analysis of necroptotic proteins in failing human hearts

Abstract

BackgroundCell loss and subsequent deterioration of contractile function are hallmarks of chronic heart failure (HF). While apoptosis has been investigated as a participant in the progression of HF, it is unlikely that it accounts for the total amount of non-functional tissue. In addition, there is evidence for the presence of necrotic cardiomyocytes in HF. Therefore, the objective of this study was to investigate the necroptotic proteins regulating necroptosis, a form of programmed necrosis, and thereby assess its potential role in human end-stage HF.MethodsLeft ventricular samples of healthy controls (C) and patients with end-stage HF due to myocardial infarction (CAD) or dilated cardiomyopathy (DCM) were studied. Immunoblotting for necroptotic and apoptotic markers was performed. Triton X-114 fractionated samples were analyzed to study differences in subcellular localization.ResultsElevated expression of RIP1 (receptor-interacting protein), pSer227-RIP3 and its total levels were observed in HF groups compared to controls. On the other hand, caspase-8 expression, a proapoptotic protease negatively regulating necroptosis, was downregulated suggesting activation of necroptosis signaling. Total mixed-lineage kinase domain-like protein (MLKL) expression did not differ among the groups; however, active cytotoxic forms of MLKL were present in all HF samples while they were expressed at almost undetectable levels in controls. Interestingly, pThr357-MLKL unlike pSer358-MLKL, was higher in DCM than CAD. In HF, the subcellular localization of both RIP3 and pThr357-MLKL was consistent with activation of necroptosis signaling. Expression of main apoptotic markers has not indicated importance of apoptosis.ConclusionsThis is the first evidence showing that human HF of CAD or DCM etiology is positive for markers of necroptosis which may be involved in the development of HF.Electronic supplementary materialThe online version of this article (doi:10.1186/s12967-017-1189-5) contains supplementary material, which is available to authorized users.

Comments to the first nomenclature of human cytology: the description of cells and their ultrastructure in the Terminologia Histologica. Which important medical and biological terms are disputable or missing?

“…The terms associated with cell deathapoptosis and anoikisare listed, but the terms necrosis and necroptosis, as a form of programmed necrosis (Szobi et al 2017), are missing.…”

Molecular mechanism and therapy application of necrosis during myocardial injury

“…In the permanent myocardial ischaemia animal model, RIP3 knockout would decrease the inflammatory response and hypertrophic growth of the cells while the ejection fraction was increased 60. It had been also observed that the markers of necrosis, phospho‐MLKL, are also up regulated in the end‐stage heart failure patients 71. Until now, several important factors which are involved in the regulation of death receptor‐mediated necrosis in the pathogenesis of heart patients have been revealed.…”

“…60 It had been also observed that the markers of necrosis, phospho-MLKL, are also up regulated in the end-stage heart failure patients. 71 Until now, several important factors which are involved in the regulation of death receptor-mediated necrosis in the pathogenesis of heart patients have been revealed.…”

The COP9 Signalosome Suppresses Cardiomyocyte Necroptosis

“…Findings from analyzing biochemical markers of necroptosis in the myocardium of humans with end-stage heart failure resulting from myocardial infarction (MI) or dilated cardiomyopathy indicate an involvement of necroptosis in the development of heart failure. 20 A genetic variant in the RIPK3 promoter region associated with increased RIPK3 transcription may contribute to the poor prognosis of heart failure patients. 21 Animal experiments demonstrated an important role for necroptosis in post-MI remodeling, 22 myocardial ischemia/reperfusion (I/R) injury, cardiotoxicity of doxorubicin treatment, 23, 24 and paraquat-induced cardiac contractile dysfunction.…”