The CO/HO system reverses inhibition of mitochondrial biogenesis and prevents murine doxorubicin cardiomyopathy
Hagir B. Suliman, Martha Sue Carraway, Abdelwahid S. Ali, Chrystal M. Reynolds, Karen E. Welty-Wolf, Claude A. Piantadosi
Hagir B. Suliman, Martha Sue Carraway, Abdelwahid S. Ali, Chrystal M. Reynolds, Karen E. Welty-Wolf, Claude A. Piantadosi
View: Text | PDF
Research Article Cardiology

The CO/HO system reverses inhibition of mitochondrial biogenesis and prevents murine doxorubicin cardiomyopathy

Abstract

The clinical utility of anthracycline anticancer agents, especially doxorubicin, is limited by a progressive toxic cardiomyopathy linked to mitochondrial damage and cardiomyocyte apoptosis. Here we demonstrate that the post-doxorubicin mouse heart fails to upregulate the nuclear program for mitochondrial biogenesis and its associated intrinsic antiapoptosis proteins, leading to severe mitochondrial DNA (mtDNA) depletion, sarcomere destruction, apoptosis, necrosis, and excessive wall stress and fibrosis. Furthermore, we exploited recent evidence that mitochondrial biogenesis is regulated by the CO/heme oxygenase (CO/HO) system to ameliorate doxorubicin cardiomyopathy in mice. We found that the myocardial pathology was averted by periodic CO inhalation, which restored mitochondrial biogenesis and circumvented intrinsic apoptosis through caspase-3 and apoptosis-inducing factor. Moreover, CO simultaneously reversed doxorubicin-induced loss of DNA binding by GATA-4 and restored critical sarcomeric proteins. In isolated rat cardiac cells, HO-1 enzyme overexpression prevented doxorubicin-induced mtDNA depletion and apoptosis via activation of Akt1/PKB and guanylate cyclase, while HO-1 gene silencing exacerbated doxorubicin-induced mtDNA depletion and apoptosis. Thus doxorubicin disrupts cardiac mitochondrial biogenesis, which promotes intrinsic apoptosis, while CO/HO promotes mitochondrial biogenesis and opposes apoptosis, forestalling fibrosis and cardiomyopathy. These findings imply that the therapeutic index of anthracycline cancer chemotherapeutics can be improved by the protection of cardiac mitochondrial biogenesis.

Authors

Hagir B. Suliman, Martha Sue Carraway, Abdelwahid S. Ali, Chrystal M. Reynolds, Karen E. Welty-Wolf, Claude A. Piantadosi

×

Figure 3

Apoptosis and mitochondrial damage after DOX treatment.

Options: View larger image (or click on image) Download as PowerPoint
Apoptosis and mitochondrial damage after DOX treatment. (A) Western blot...
(A) Western blot analysis of caspase-3 using antibody that recognizes the full-length molecule (37-kDa band) and the 17-kDa proteolytic-cleavage fragment. Western blot analysis was also performed using anti-AIF antibody that detects mitochondrial and nuclear AIF. Note that CO prevented caspase-3 cleavage and AIF release after DOX, but HH did not. (B–P) Photomicrographs of immunolabeling for laminin (red), GFP-mitochondria (green), and overlay in mouse heart. (B–D) Control LV shows intense laminin labeling in the endomysium framing the cardiomyocytes and small vessels. CO alone did not alter the distribution or intensity of laminin or mitochondrial fluorescence (E–G), whereas laminin in DOX-treated mice outlined both living and degenerating or dead cardiomyocytes by loss of intensity of mitochondrial fluorescence (H–J). Improvement in DOX-treated mice was seen after 1 (K–M) or 2 CO doses (N–P). Original magnification, ×300. (Q) Quantification of mitochondrial fluorescence intensity relative to laminin. Values are mean ± SEM data for 6 mice per group. (R) The effects of DOX and CO treatment on the protein carbonyl content of cardiac mitochondria by anti-dinitrophenol dot blotting and quantification by densitometry. Each bar graph represents mean ± SEM of 6 mice. (S) Histogram of real-time PCR data for cellular mtDNA content showing decreases after DOX are prevented by CO but not by HH. *P < 0.05 versus other groups; †P < 0.05 versus control.