Hypothesis: Elucidation of circadian rhythms in hiPSCs differentiated cardiomyocytes.

Conclusions: Our study established the CRISPR gRNA design can be used study splicing and circadian pattern regulated by connexin 43.

Results: To determine the genomic regulatory elements that control exon splicing we designed several guides Per1, Per2, and Connexin 43. Our sequencing and bioinformatics analysis found untranslated region or coding region designed guide RNA found changes in splicing but protein truncation observed in connexin 43 of the coding region. To further understand the differential expression of Cx43 in hiPSC-CMs optical mapping in monolayers and spheroids were observed decreased conduction velocities. To further understand we also perform impedance measurement in WT, Cx43 KO, and Cx43-OV. We found resistivity and reactivity were significantly changed between groups. We will look these mechanisms has any role in the spheroid treatment is associated with significant changes in arrhythmogenicity of swine studies.

Methods: In the current investigation, hiPSCs carrying knockout mutations for Per1, Per2, and connexin43 were generated via CRISPR/Cas9 gene-editing technology. hiPSCs were differentiated into cardiomyocytes (CM) and spheroid cultured was performed as previously described. We evaluated different guide RNAs Cas9-induced DNA double-stranded break were analyzed using Sanger sequencing and bioinformatics. Optical mapping was used to measure the electrical properties of individual spheroids and monolayers of WT, connexin 43 KO, and overexpression of connexin 43 (WT, Cx43 KO, and Cx43 OV). We also study in the hiPSCs CMs of monolayer resistivity and reactivity and compared them with rabbit ventricular myocardium.