Differential Expression of Members of SOX Family of Transcription Factors in Failing Human Hearts.

Abstract

The Sry-related high-mobility-group box (SOX) gene family, with 20 known transcription factors in humans, plays an essential role during development and disease processes. Several SOX proteins (SOX4, 11, and 9) are required for normal heart morphogenesis. SOX9 was shown to contribute to cardiac fibrosis. However, differential expression of other SOXs and their roles in the failing human myocardium have not been explored. Here we used the whole-transcriptome sequencing (RNA-seq), gene co-expression, and meta-analysis to examine whether any SOX factors might play a role in the failing human myocardium. RNA-seq analysis was performed for cardiac tissue samples from heart failure (HF) patients due to dilated cardiomyopathy (DCM), or hypertrophic cardiomyopathy (HCM) and healthy donors (NF). The RNA levels of 20 SOX genes from RNA-seq data were extracted and compared to the three groups. Four SOX genes whose RNA levels were significantly upregulated in DCM or HCM compared to NF. However, only SOX4 and SOX8 proteins were markedly increased in the HF groups. A moderate to strong correlation was observed between the RNA level of SOX4/8 and fibrotic genes among each individual. Gene co-expression network analysis identified genes associated and respond similarly to perturbations with SOX4 in cardiac tissues. Using a meta-analysis combining epigenetics and genome-wide association data, we reported several genomic variants associated with HF phenotype linked to SOX4 or SOX8. In summary, our results implicate that SOX4 and SOX8 have a role in cardiomyopathy, leading to HF in humans. The molecular mechanism associated with them in HF warrants further investigation. BACKGROUND: : Heart failure (HF) affects 5.7 million people in the U.S. with more than 500,000 new cases added annually. New therapeutic strategies remain needed for HF. The cardiac-pathological features are driven by transcriptome reprogramming. Understanding transcriptional control of HF is beneficial for developing novel therapies. TRANSLATIONAL SIGNIFICANCE: : This study revealed that SOX4 and SOX8 were significantly increased in cardiac tissues of HF patients and the HF-genetic variants and epigenetic changes associated with these two genes. Understanding the role of SOX4 and SOX8 in failing human myocardium and gene regulatory networks related to them may help to identify potential therapeutic targets for HF.