Mandatory role of endoplasmic reticulum and its pentose phosphate shunt in the myocardial defense mechanisms against the redox stress induced by anthracyclines

Figures

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  Fig. 1. H6PD intracellular localization and its role in ER-mitochondria organization. A H6PD activity, expressed as glucose dehydrogenation rate, and B G6PD activity, expressed as the G6P dehydrogenation rate, of mitochondria (Mit) and microsomal fraction (MS) harvested from hepatocytes of wild-type (WT, green columns) and H6PD KO (H6PD−/−, red columns) mice before the start of doxorubicin treatment. Representative electron microscopy images of liver harvested from WT (C) and H6PD (D) mice, showing nucleus (N) and the ultrastructure of mitochondria (M) and endoplasmic reticulum (ER). E Body weight and F serum glucose concentration of WT (green columns) and H6PD−/− (red columns) mice before the start of doxorubicin treatment. Data are expressed as mean ± SD. ** = p < 0.01

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  Fig. 2. DXR treatment effect on survival, body weight and FDG uptake of H6PD knock-out mice. A Kaplan-Meyer curves for the survival time during doxorubicin treatment in wild-type (WT, green line) and H6PD knock-out (H6PD−/−, red line) mice. B Weight changes over time, expressed as % of weight at start of treatment (week #0), in WT (green line) and H6PD−/− (red line) mice of untreated (circle) and doxorubicin treated (square) groups. C Myocardial FDG average Standardized Uptake Value (SUV), D myocardial maximal SUV and E heart volume of WT (green) and H6PD−/− (red) mice of untreated and doxorubicin treated (DXR) groups evaluated 1 week after the last injection of doxorubicin. F Bladder volume and FDG content in untreated and DXR groups of WT (green) and H6PD−/− (red) mice. Data are expressed as mean ± SD. ** = p < 0.01, *** = p < 0.001 and **** = p < 0.0001

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  Fig. 3. Role of H6PD in FDG retention and myocardial structure under DXR-induced redox stress. Representative images showing FDG average Standardized Uptake Value (SUV) of whole-body mice and hematoxylin–eosin staining of heart harvested from wild-type (WT, panels A and C) and H6PD knock-out (H6PD−/−, panels B and D) of untreated (panels A and B) and doxorubicin treated (DXR, panels C and D) groups. E Cardiomyocytes nuclear density evaluated in myocardial section of WT (green columns) and H6PD−/− (red columns) mice of both untreated (solid columns) and DXR (dashed columns) groups. Data are expressed as mean ± SD. * = p < 0.05 and ** = p < 0.01

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  Fig. 4. DXR effect on oxidative damage and its impact on Ca2+ exchange between ER and mitochondria in H6PD knock-out mice. A H6PD and B G6PD protein expression, expressed as relative optical density (ROD), in heart homogenates harvested from wild-type (WT, green) and H6PD knock-out (H6PD−/− red) of untreated and doxorubicin treated (DXR) groups. C Malondialdehyde concentration, D total antioxidant capacity and E their correlation in hearts harvested from WT (green) and H6PD−/− (red) of untreated (circles) and DXR (squares) groups. Protein expression of F G6PT and calnexin G as well as mRNA levels of H SERCA2 and I RyR2 evaluated in hearts harvested from WT (green) and H6PD−/− (red) mice of untreated (circles) and DXR (squares) groups. K Representative western blot signals of H6PD, G6PD G6PT, calnexin proteins and alpha-Tubulin, used as the housekeeping protein J. Data are expressed as mean ± SD. * = p < 0.05, ** = p < 0.01 and *** = p < 0.001

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  Fig. 5. H6PD role in the preservation of mitochondria ultrastructure after DXR-induced redox stress. Representative electron microscopy images of heart harvested from wild-type (WT, panels A and C) and H6PD knock-out H6PD−/−, panels B and D) of untreated (panels A and B) and doxorubicin treated (DXR, panels C and D) groups. E Mitochondrial area of WT (green) and H6PD−/− mice (red) of both untreated and DXR groups. F Evaluation of cristae preservation in the myocardium of WT (green columns) and H6PD−/− (red columns) mice of untreated (solid columns) and DXR (red columns) groups. Data are expressed as mean ± SD. ** = p < 0.01, *** = p < 0.001 and **** = p < 0.0001