Temporal Orchestration of Krüppel-like Factors During Cardiac Remodeling Following Isoproterenol-Induced Myocardial Injury

Figures

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  Figure 1. Isoproterenol-induced cardiac injury and hypertrophic remodeling. (A) Representative images illustrating the surgical procedure for heart exposure and excision. (B) Gross morphology of excised hearts, showing a representative control heart (left) and a heart collected 21 days after isoproterenol administration (right), evidencing cardiac enlargement. (C) Relative gene expression of atrial natriuretic peptide (ANP, cardiac stress marker) and α-myosin heavy chain (α-MHC, hypertrophic marker) assessed by qRT-PCR in control (black) and isoproterenol-treated rats at Day 1 and Day 3 post-administration (red). Gene expression levels were normalized to GAPDH and expressed as mean ± SEM. *** p < 0.001 vs. control. (D) Cardiac volume, calculated using the formula V = (3/4) π × D1 × D2 × L and normalized to body weight (y-axis), plotted across the experimental time course (x-axis) in control and treated rats. Statistical comparisons were performed using one-way ANOVA followed by Dunnett’s post hoc test (two-sided). *** p < 0.001 vs. control.

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  Figure 2. Temporal transcriptional dynamics of Krüppel-like factors, cardiac remodeling markers, and inflammatory genes following isoproterenol-induced cardiac injury. (A) Heatmap of KLF family gene expression and related genes in normal human heart tissue (TPM), compared to fibroblasts as a noncardiac control. (B) Temporal heatmap showing relative expression patterns of selected KLFs and inflammatory genes across different days after heart injury, illustrating early-, mid-, and late-stage remodeling phases. (C) RT–qPCR analysis of representative remodeling-associated genes, KLFs, and inflammatory markers. The x-axis denotes days after isoproterenol administration, and the y-axis represents relative gene expression normalized to GAPDH.

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  Figure 3. Temporal transcriptional profiling of cardiac electrical conduction and excitation–contraction coupling genes during isoproterenol-induced cardiac remodeling. (A) Heatmap of electrical and excitation–contraction coupling genes in normal human heart tissue (TPM). (B) Relative expression changes in genes involved in electrical signaling, gap junction communication, and selected regulatory and inflammatory markers across different days following cardiac injury. (C) RT–qPCR validation of representative cardiac regulatory, electrical, and inflammatory genes. Relative gene expression was normalized to GAPDH.

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  Figure 4. Protein–protein interaction network of Krüppel-like factor (KLF) family members and associated cardiac regulatory genes. (A) Protein–protein interaction network generated using the STRING database (version 11.5), showing predicted and experimentally derived associations among KLFs and genes associated with cardiac hypertrophy, fibrosis, inflammatory signaling, and electrical conduction. Nodes represent proteins, and edges indicate known or predicted interactions based on experimental evidence, co-expression, gene neighborhood, text mining, and curated database annotations. (B) Venn diagram illustrating the overlap of genes associated with distinct KLF family members, grouped according to their structural classification: subgroup 1 (KLF3, KLF8, KLF12), subgroup 2 (KLF1, KLF2, KLF4, KLF5, KLF6, KLF7), subgroup 3 (KLF9, KLF10, KLF11, KLF13, KLF14, KLF16), and ungrouped members (KLF15 and KLF17).