Personalized in vitro models reveal functional impact of a KCNH2 mutation and enable drug screening in LQTS2

Bingyu Zheng; Yue Zhu; Mingyu Sun; Hongyi Cheng; Shimeng Zhang; Cheng Cai; Kai Gu; Yanzun An; Xiangwei Ding; Feng Zhang; Chang Cui; Minglong Chen

doi:10.1016/j.hroo.2025.12.022

Personalized in vitro models reveal functional impact of a KCNH2 mutation and enable drug screening in LQTS2

Heart Rhythm O2. 2026 Jan 8;7(3):522-534. doi: 10.1016/j.hroo.2025.12.022. eCollection 2026 Mar.

Authors

Bingyu Zheng¹, Yue Zhu¹, Mingyu Sun², Hongyi Cheng¹, Shimeng Zhang¹, Cheng Cai¹, Kai Gu¹, Yanzun An³, Xiangwei Ding⁴, Feng Zhang¹, Chang Cui¹, Minglong Chen¹

Affiliations

¹ Division of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
² Department of Cardiovascular Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China.
³ Honor's College, Capital Normal University, Beijing, China.
⁴ The Affiliated Taizhou People's Hospital of Nanjing Medical University, Taizhou School of Clinical Medicine, Nanjing Medical University, Taizhou, China.

Abstract

Background: Long QT syndrome is clinically associated with recurrent ventricular tachycardia and sudden cardiac death. Mutations in KCNH2, which encodes the pore-forming potassium channel subunit human ether-a-go-go-related gene (Kv11.1), are associated with long QT syndrome type 2 (LQTS2).

Objective: We aimed to investigate the pathogenicity and personalized therapy for a patient with LQTS2 carrying a novel KCNH2 heterozygous mutation F431L.

Methods: This study aimed to evaluate the expression and function of the channel protein, we conducted immunoblotting and whole-cell patch-clamp recordings. In addition, patient-specific human-induced pluripotent stem cell-derived cardiomyocytes were combined with a heart-on-chip platform to validate the pathogenicity of this heterozygous variant and investigate the pharmacologic candidates for phenotypic rescue.

Results: In HEK293 cells overexpressing the mutant KCNH2, a significant reduction in human ether-a-go-go-related gene membrane abundance was observed. The heterozygous variant led to decreased current density and alterations in voltage-dependent activation (positively shifted) and inactivation (negatively shifted) compared with the wild type. Correspondingly, patient-specific human-induced pluripotent stem cell-derived cardiomyocytes harboring the heterozygous KCNH2 F431L mutation displayed reduced current density and prolonged action potential duration. Moreover, LQTS2 patient-specific engineered cardiac tissues replicated the disease phenotype with extended field potential duration. Drug screening on the heart-on-chip platform indicated the potential therapeutic efficacy of the slowly activating delayed rectifier potassium current channel agonist ML277 and the proteasome inhibitor MG101.

Conclusion: The F431L mutation in KCNH2 was pathogenic, characterized by both channel instability and functional impairments. Our study also highlighted the feasibility of using a patient-specific microphysiological system for individualized treatment in ion-channel diseases.

Keywords: Field potential; Heart-on-chip; Human ether-a-go-go-related gene (hERG); Long QT syndrome 2; iPSC-CMs.