TECRL deficiency results in aberrant mitochondrial function in cardiomyocytes

The endoplasmic reticulum protein TECRL promotes mitochondrial function in cardiomyocytes and its knockout in mice leads to cardiac dysfunction, decreased mitochondria function, and elevated levels of reactive oxygen species. Sudden cardiac death (SCD) caused by ventricular arrhythmias is the leading cause of mortality of cardiovascular disease. Mutation in TECRL, an endoplasmic reticulum protein, was first reported in catecholaminergic polymorphic ventricular tachycardia during which a patient succumbed to SCD. Using loss- and gain-of-function approaches, we investigated the role of TECRL in murine and human cardiomyocytes. Tecrl (knockout, KO) mouse shows significantly aggravated cardiac dysfunction, evidenced by the decrease of ejection fraction and fractional shortening. Mechanistically, TECRL deficiency impairs mitochondrial respiration, which is characterized by reduced adenosine triphosphate production, increased fatty acid synthase (FAS) and reactive oxygen species production, along with decreased MFN2, p-AKT (Ser473), and NRF2 expressions. Overexpression of TECRL induces mitochondrial respiration, in PI3K/AKT dependent manner. TECRL regulates mitochondrial function mainly through PI3K/AKT signaling and the mitochondrial fusion protein MFN2. Apoptosis inducing factor (AIF) and cytochrome C (Cyc) is released from the mitochondria into the cytoplasm after siTECRL infection, as demonstrated by immunofluorescent staining and western blotting. Herein, we propose a previously unrecognized TECRL mechanism in regulating CPVT and may provide possible support for therapeutic target in CPVT.

Automated summary

TECRL plays a critical role in promoting mitochondrial function in cardiomyocytes, and its deficiency can lead to cardiac dysfunction and increased levels of reactive oxygen species. On the other hand, overexpression of TECRL can enhance mitochondrial respiration. These findings provide new insights for the treatment of catecholaminergic polymorphic ventricular tachycardia.