SMYD1 modulates the proliferation of multipotent cardiac progenitor cells derived from human pluripotent stem cells during myocardial differentiation through GSK3β/β-catenin/ERK signaling

Background: The histone-lysine N-methyltransferase SMYD1, which is specific to striated muscle, plays a crucial role in regulating early heart development. Its deficiency has been linked to the occurrence of congenital heart disease. Nevertheless, the precise mechanism by which SMYD1 deficiency contributes to congenital heart disease remains unclear. Methods: We established a SMYD1 knockout pluripotent stem cell line and a doxycyclineinducible SMYD1 expression pluripotent stem cell line to investigate the functions of SMYD1 utilizing an in vitro-directed myocardial differentiation model. Results: Cardiomyocytes lacking SMYD1 displayed drastically diminished differentiation efficiency, concomitant with heightened proliferation of cardiac progenitor cells during the early cardiac differentiation stage. These cellular phenotypes were confirmed through experiments inducing the re-expression of SMYD1. Transcriptome sequencing and small molecule inhibitor intervention suggested that the GSK3β/β-catenin/ERK signaling pathway was involved in the proliferation of cardiac progenitor cells. Chromatin immunoprecipitation demonstrated that SMYD1 acted as a transcriptional activator of GSK3β through histone H3 Lysine 4 trimethylation. Additionally, dualluciferase analyses indicated that SMYD1 could interact with the promoter region of GSK3β, thereby augmenting its transcriptional activity. Moreover, administering insulin and Insulin-like growth factor 1 can enhance the efficacy of myocardial differentiation in SMYD1 knockout cells. Conclusions: Our research indicated that the participation of SMYD1 in the GSK3β/β-catenin/ERK signaling cascade modulated the proliferation of cardiac progenitor cells during myocardial differentiation. This process was partly reliant on the transcription of GSK3β. Our research provided a novel insight into the genetic modification effect of SMYD1 during early myocardial differentiation. The findings were essential to the molecular mechanism and potential interventions for congenital heart disease. To investigate the function SMYD1 in human pluripotent stem cell differentiation into cardiomyocytes, we established SMYD1 knockout cell lines through the Crispr Cas9 system. We then performed gene expression analysis using data obtained from RNA-seq of 2 different cells at cardiac progenitor cells stage during myocardial differentiation. Comparative gene expression profling analysis of RNA-seq data for hESC cells and SMYD1 knockout cells at cardiac progenitor cells stage during myocardial differentiation.