Ribonuclease 1 attenuates septic cardiomyopathy and cardiac apoptosis in a murine model of polymicrobial sepsis
Elisabeth Zechendorf, Caroline E. O’Riordan, Lara Stiehler, Natalie Wischmeyer, Fausto Chiazza, Debora Collotta, Bernd Denecke, Sabrina Ernst, Gerhard Müller-Newen, Sina M. Coldewey, Bianka Wissuwa, Massimo Collino, Tim-Philipp Simon, Tobias Schuerholz, Christian Stoppe, Gernot Marx, Christoph Thiemermann, Lukas Martin
Elisabeth Zechendorf, Caroline E. O’Riordan, Lara Stiehler, Natalie Wischmeyer, Fausto Chiazza, Debora Collotta, Bernd Denecke, Sabrina Ernst, Gerhard Müller-Newen, Sina M. Coldewey, Bianka Wissuwa, Massimo Collino, Tim-Philipp Simon, Tobias Schuerholz, Christian Stoppe, Gernot Marx, Christoph Thiemermann, Lukas Martin
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Research Article Immunology Inflammation

Ribonuclease 1 attenuates septic cardiomyopathy and cardiac apoptosis in a murine model of polymicrobial sepsis

Abstract

Septic cardiomyopathy is a life-threatening organ dysfunction caused by sepsis. Ribonuclease 1 (RNase 1) belongs to a group of host-defense peptides that specifically cleave extracellular RNA (eRNA). The activity of RNase 1 is inhibited by ribonuclease-inhibitor 1 (RNH1). However, the role of RNase 1 in septic cardiomyopathy and associated cardiac apoptosis is completely unknown. Here, we show that sepsis resulted in a significant increase in RNH1 and eRNA serum levels compared with those of healthy subjects. Treatment with RNase 1 resulted in a significant decrease of apoptosis, induced by the intrinsic pathway, and TNF expression in murine cardiomyocytes exposed to either necrotic cardiomyocytes or serum of septic patients for 16 hours. Additionally, treatment of septic mice with RNase 1 resulted in a reduction in cardiac apoptosis, TNF expression, and septic cardiomyopathy. These data demonstrate that eRNA plays a crucial role in the pathophysiology of the organ (cardiac) dysfunction in sepsis and that RNase and RNH1 may be new therapeutic targets and/or strategies to reduce the cardiac injury and dysfunction caused by sepsis.

Authors

Elisabeth Zechendorf, Caroline E. O’Riordan, Lara Stiehler, Natalie Wischmeyer, Fausto Chiazza, Debora Collotta, Bernd Denecke, Sabrina Ernst, Gerhard Müller-Newen, Sina M. Coldewey, Bianka Wissuwa, Massimo Collino, Tim-Philipp Simon, Tobias Schuerholz, Christian Stoppe, Gernot Marx, Christoph Thiemermann, Lukas Martin

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Figure 3

RNase 1 treatment of cardiomyocytes exposed to necrotic cardiomyocytes results in decreased apoptosis.

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RNase 1 treatment of cardiomyocytes exposed to necrotic cardiomyocytes r...
Cardiomyocytes exposed to 105 necrotic cardiomyocytes in presence (RNase + NC) or absence (NC) of 2.8 U/mL RNase 1 for 16 hours compared with unstimulated cells (control) were analyzed (all n = 3). (A) Apoptotic cells were labeled with TUNEL (red) and the nuclei of cardiomyocytes stained with DAPI (blue). Scale bars: 100 μm. (B) Quantification of TUNEL fluorescence. A 1-way ANOVA followed by Bonferroni test was used for multiple comparisons. Data are presented as dot plot with the mean ± SEM. (C) Treated HL-1 cells were stained with annexin V and 7-AAD and analyzed by flow cytometry. Gate I (bottom left) displays the living cells. The annexin V+ cells are shown in Gate II (top left) and represent the apoptotic cardiomyocytes. The double-positive cells are demonstrated in gate III (top right) and in gate IV (bottom right), where the 7-AAD+ or necrotic cells are located. (D) The percentage of annexin V+ (apoptotic) cells is displayed. A 1-way ANOVA followed by Bonferroni test was used for multiple comparisons. Data are presented as dot plot with the mean ± SEM. §P < 0.05 versus control; #P < 0.05 versus NC. NC, necrotic cardiomyocytes; RNase, ribonuclease 1.