Essential role of NONO-HOXA1-Wnt axis in cardiomyocyte differentiation.

NONO is recognized as a critical molecular scaffold involved in both transcriptional and posttranscriptional regulation. Mutations in NONO are frequently linked to congenital heart diseases (CHDs) in humans. However, the mechanisms by which NONO regulates cardiac development remain elusive. Here, we identified NONO as a pivotal dual-function regulator of cardiomyocyte differentiation in human induced pluripotent stem cells (hiPSCs). NONO deficiency in hiPSCs results in a distinct defect in early cardiomyocyte differentiation. Mechanistically, NONO interacts with HOXA1 and regulates the dynamic expression of key genes during early cardiomyocyte differentiation. ChIP-seq analysis reveals that NONO loss reduces HOXA1 occupancy at target genes, compromising its transcriptional regulation. Additionally, NONO and HOXA1 cooperatively activate the Wnt signaling. Taken together, these findings establish the NONO-HOXA1-Wnt axis as a key molecular mechanism in cardiomyocyte differentiation and provide insights into the etiology of CHDs associated with NONO mutations.