Date of download: 6/22/2016 Copyright © The American College of Cardiology. All rights reserved. From: Increased Expression of Adenosine Triphosphate-Sensitive K+ Channels in Mitral Dysfunction: Mechanically Stimulated Transcription and Hypoxia-Induced Protein Stability? J Am Coll Cardiol. 2012;59(4): doi: /j.jacc Expression of Kir6.2 Protein in Left Heart at Different Venous PO 2 (Top) Examples of Western blots of potassium inward rectifier (Kir) 6.2 protein of right atrium (RA), left atrium (LA), right ventricle (RV), and left ventricle (LV) for 4 patients, with various venous PO 2. Red Ponceau staining mostly shows equal loading of wells. (Bottom) Significant inverse correlations in left heart of all patients between Kir6.2 and venous PO 2 (lowest LA not considered). Correlations for right heart were not significant (not shown). Figure Legend:

Date of download: 6/22/2016 Copyright © The American College of Cardiology. All rights reserved. From: Increased Expression of Adenosine Triphosphate-Sensitive K+ Channels in Mitral Dysfunction: Mechanically Stimulated Transcription and Hypoxia-Induced Protein Stability? J Am Coll Cardiol. 2012;59(4): doi: /j.jacc Immunohistochemistry and Detection of Kir6.2 in Tissue Sections (Top) Representative regions show tissues immunolabeled with anti-potassium inward rectifier (Kir) 6.2 antibody, (Bottom) The same tissues where all cells with Kir6.2 labeling above threshold were evenly stained using MetaMorph software. The pairs of panels of different patients are displayed in descending order of venous PO 2. Note the increased staining at low PO 2. Figure Legend:

Date of download: 6/22/2016 Copyright © The American College of Cardiology. All rights reserved. From: Increased Expression of Adenosine Triphosphate-Sensitive K+ Channels in Mitral Dysfunction: Mechanically Stimulated Transcription and Hypoxia-Induced Protein Stability? J Am Coll Cardiol. 2012;59(4): doi: /j.jacc Relationships Between Blood Gases, mRNAs, and Proteins All values for left heart parameters and variables were ranked, and linear or quadratic relationships determined by SPSS and Origin 6.0 software. The p values are color coded (Online Fig. 2 lists p, N, and R). Quadratic relationships are marked by either ∪ or ∩ symbols to indicate a U-curve or bell-shaped curve, respectively. Note venous PO 2 dependence of potassium inward rectifier (Kir) 6.2 protein, lack of correlations between Kir6 messenger ribonucleic acids (mRNAs) and proteins, and similar patterns for LV and LA. The same analysis was applied to RV and RA (Online Fig. 3), and no PO 2 dependence of Kir6 proteins was detected in right heart. FOX = forkhead box; HIF = hypoxia-inducible factor; other abbreviations as in Figure 1. Figure Legend:

Date of download: 6/22/2016 Copyright © The American College of Cardiology. All rights reserved. From: Increased Expression of Adenosine Triphosphate-Sensitive K+ Channels in Mitral Dysfunction: Mechanically Stimulated Transcription and Hypoxia-Induced Protein Stability? J Am Coll Cardiol. 2012;59(4): doi: /j.jacc Relationships Between Mechanical and Echocardiographic Parameters, mRNAs, and Proteins All values for left heart parameters and variables were ranked, and linear or quadratic relationships determined by SPSS and Origin 6.0 software. Symbols of display are as described in legend to Figure 3 (Online Fig. 5 lists p, N, and R). Note pressure dependence of HIF-1α and/or potassium inward rectifier (Kir) 6.2 messenger ribonucleic acids (mRNAs) expression, but more distinct patterns between LV and LA than in Figure 3. The same analysis was applied to RV and RA (Online Fig. 6). AP = aortic pressure; D = diameter; LAP = left atrial pressure; LVP = left ventricular pressure; RAP/CVP = right atrial pressure/central venous pressure; S = section; other abbreviations as in Figures 1 and 3. Figure Legend:

Date of download: 6/22/2016 Copyright © The American College of Cardiology. All rights reserved. From: Increased Expression of Adenosine Triphosphate-Sensitive K+ Channels in Mitral Dysfunction: Mechanically Stimulated Transcription and Hypoxia-Induced Protein Stability? J Am Coll Cardiol. 2012;59(4): doi: /j.jacc Left Ventricular Kir6.2 in Patients With Mitral Regurgitation The panels of Figures 3 and 4 suggest that ventricular distension by mitral regurgitation and aortic pressure head (“mechanical stress”) causes increased hypoxia-inducible factor (HIF)-1α and potassium inward rectifier (Kir) 6.2 messenger ribonucleic acid (mRNA) expression (gray). Tissue hypoxia, conversely, increased Kir6.2 protein (red), most probably by inhibition of the proteasomal Kir6.2 degradation pathway (see text). Figure Legend: