EGR1 Is Implicated in Right Ventricular Cardiac Remodeling Associated with Pulmonary Hypertension

Figures

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  Figure 1. Study design. Cardiac biopsies were acquired intraoperatively and 3 months after surgery. Transcriptional signatures were investigated using a microarray and further biocomputational analyses. Lastly, results were validated using immunocytochemistry. CTEPH, chronic thromboembolic pulmonary hypertension; DEGs, differentially expressed genes; GO, gene ontology; iPAH, idiopathic pulmonary arterial hypertension; LuTX, lung transplantation; PEA, pulmonary endarterectomy; RVH, right ventricular hypertrophy; TFBS, transcription factor binding site.

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  Figure 2. Gene expression signatures of hypertrophic myocardium of iPAH patients before LuTX and reverse remodeled hearts 3 months after surgery. (A) PCA of samples before PEA and 3 months after PEA. Each dot represents one donor; colors indicate time points. (B) Volcano plot depicting DEGs as a function of fold change and statistical significance. Each dot represents one gene. Red and green indicate up- and downregulated genes, respectively. Insert shows absolute numbers of DEGs when comparing before surgery and after recovery. Red and green bars indicate up- and downregulated genes, respectively. (C) Heatmap of DEGs. Each row represents one donor at a certain time point; each line indicates one gene. Red and blue indicate up- and downregulation, respectively. (D) Heatmaps of down- (green) and upregulated genes (red) are shown. Colors indicate absolute, average log2-transformed expression values. Gene ontologies associated with (E) down- and (F) upregulated DEGs. Each circle represents one ontology. Colors indicate p-values.

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  Figure 3. Gene expression profiles of hypertrophic myocardium of CTEPH patients before PEA and reverse remodeled hearts 3 months after surgery. (A) PCA of samples before PEA and 3 months after PEA. Each dot represents one donor; colors indicate time points. (B) Volcano plot depicting DEGs as a function of fold change and statistical significance. Each dot represents one gene. Red and green indicate up- and downregulated genes, respectively. Insert shows absolute numbers of DEGs before surgery and after recovery. Red and green bars indicate up- and downregulated genes, respectively. (C) Heatmap of DEGs. Each row represents one donor at a certain time point; each line indicates one gene. Red and blue indicate up- and downregulation, respectively. (D) Heatmaps of down- (green) and upregulated genes (red) are shown. Colors indicate absolute, average log2-transformed expression values. Gene ontologies associated with (E) down- and (F) upregulated DEGs. Each circle represents one ontology; colors indicate p-values.

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  Figure 4. Identification of TFs governing postoperative reverse cardiac remodeling. (A) Genes highly expressed preoperatively and downregulated 3 months after surgery were screened for TFBS. Factors identified in (A) iPAH and (C) CTEPH are depicted as a function of z- and Fisher scores. An area-proportional Venn diagram of overlapping DEGs and TFs identified by TFBS analysis in (B) iPAH and (D) CTEPH patients. Numbers indicate absolute number of genes. (E) Average expression values of EGR1 downstream genes of iPAH and CTEPH patients. Fold-change expression was determined by comparing pre- and postsurgery values. (F) Histocytochemistry of EGR1 in the hypertrophic right ventricle of a PH patient. One representative micrograph of n = 3 donors is shown. Scale bar = 100 µm.