Repurposing polyamines to prevent life-threatening arrhythmias in Short QT Syndrome type 3.

Moreno-Manuel, Ana I; Cruz, Francisco M; Macías, Álvaro; Cabrera-Borrego, Eva; Jalife, José · Nat Commun · 2026

basic_science · Level V

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Abstract

Short QT Syndrome type 3 (SQTS3) is an inherited disorder marked by an abnormally short QT interval on ECG and a high risk of life-threatening arrhythmias, for which effective targeted therapies are lacking. SQTS3 is caused by Kir2.1 mutations that enhance the outward component of the strong inward rectifier potassium current (I<sub>K1</sub>), disrupting its normal voltage-dependent regulation and severely abbreviating the cardiac action potential. Using a mouse model of SQTS3 carrying the Kir2.1<sup>M301K</sup> mutation, we examine whether administration of polyamines, the fundamental blockers of Kir2.1 channels, could restore the normal QT interval and prevent arrhythmia. Male mutant mice display reduced I<sub>K1</sub> rectification, reduced sodium channel function, QT interval shortening, and a high susceptibility to induced ventricular tachycardia. Here, we show that systemic polyamine administration restores strong I<sub>K1</sub> rectification, rescues sodium current density, prolongs action potential duration and QT interval, and significantly reduces arrhythmia inducibility, identifying a potential therapeutic approach for SQTS, a life-threatening disease.