Mutant ANP induces mitochondrial and ion channel remodeling in a human iPSC–derived atrial fibrillation model
Olivia T. Ly, Hanna Chen, Grace E. Brown, Liang Hong, Xinge Wang, Yong Duk Han, Mahmud Arif Pavel, Arvind Sridhar, Mark Maienschein-Cline, Brandon Chalazan, Sang-Ging Ong, Khaled Abdelhady, Malek Massad, Lona Ernst Rizkallah, Jalees Rehman, Salman R. Khetani, Dawood Darbar
Olivia T. Ly, Hanna Chen, Grace E. Brown, Liang Hong, Xinge Wang, Yong Duk Han, Mahmud Arif Pavel, Arvind Sridhar, Mark Maienschein-Cline, Brandon Chalazan, Sang-Ging Ong, Khaled Abdelhady, Malek Massad, Lona Ernst Rizkallah, Jalees Rehman, Salman R. Khetani, Dawood Darbar
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Research Article Cardiology Genetics

Mutant ANP induces mitochondrial and ion channel remodeling in a human iPSC–derived atrial fibrillation model

Abstract

Human induced pluripotent stem cell–derived cardiomyocytes (iPSC-CMs) can model heritable arrhythmias to personalize therapies for individual patients. Although atrial fibrillation (AF) is a leading cause of cardiovascular morbidity and mortality, current platforms to generate iPSC-atrial (a) CMs are inadequate for modeling AF. We applied a combinatorial engineering approach, which integrated multiple physiological cues, including metabolic conditioning and electrical stimulation, to generate mature iPSC-aCMs. Using the patient’s own atrial tissue as a gold standard benchmark, we assessed the electrophysiological, structural, metabolic, and molecular maturation of iPSC-aCMs. Unbiased transcriptomic analysis and inference from gene regulatory networks identified key gene expression pathways and transcription factors mediating atrial development and maturation. Only mature iPSC-aCMs generated from patients with heritable AF carrying the non-ion channel gene (NPPA) mutation showed enhanced expression and function of a cardiac potassium channel and revealed mitochondrial electron transport chain dysfunction. Collectively, we propose that ion channel remodeling in conjunction with metabolic defects created an electrophysiological substrate for AF. Overall, our electro-metabolic approach generated mature human iPSC-aCMs that unmasked the underlying mechanism of the first non-ion channel gene, NPPA, that causes AF. Our maturation approach will allow for the investigation of the molecular underpinnings of heritable AF and the development of personalized therapies.

Authors

Olivia T. Ly, Hanna Chen, Grace E. Brown, Liang Hong, Xinge Wang, Yong Duk Han, Mahmud Arif Pavel, Arvind Sridhar, Mark Maienschein-Cline, Brandon Chalazan, Sang-Ging Ong, Khaled Abdelhady, Malek Massad, Lona Ernst Rizkallah, Jalees Rehman, Salman R. Khetani, Dawood Darbar

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Figure 4

Unbiased transcriptomic analysis and gene regulatory network analysis identifies key Gene Ontology pathways and transcription factors mediating iPSC-aCM development and maturation.

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Unbiased transcriptomic analysis and gene regulatory network analysis id...
(A) Venn diagram showing the number of intersected upregulated differentially expressed genes (DEGs) among the 3 major comparisons: EMM iPSC-aCMs vs. HAT from the same patient, baseline iPSC-aCMs vs. HAT from the same patient, and EMM iPSC-aCMs vs. baseline iPSC-aCMs. (B) Heatmap of top upregulated and downregulated GO terms associated with DEGs comparing baseline iPSC-aCMs vs. EMM iPSC-aCMs vs. HAT from the same patients. The top GO terms upregulated were related to oxidative phosphorylation and mature methods of metabolism, myofibril assembly and structural development, and heart contraction. The top GO terms downregulated were related to embryonic and fetal processes. (C–E) Heatmaps of top upregulated and downregulated DEGs associated with the key GO pathways heart contraction (GO: 0060047) (C), myofibril assembly (GO: 0030239) (D), and oxidative phosphorylation (GO: 0006119) (E). (F and G) TF regulatory networks examining temporal development of TF regulation of the pathway heart contraction during maturation, comparing day 25 (midway through maturation) with day 15 (prior to initiation of maturation) (F) and day 32 (after maturation) versus day 25 (G). Increased target enrichment of upregulated genes overall and specific to each TF, as well as differential patterns of ion channel regulation at progressive time points, provide novel insights into temporal development and maturation of the pathway heart contraction.