LncRNA KCNQ1OT1 Mediates Pyroptosis in Diabetic Cardiomyopathy

Background/aims: Diabetic cardiomyopathy (DCM) is a common complication of diabetes and can cause heart failure, arrhythmia and sudden death. The pathogenesis of DCM includes altered metabolism, mitochondrial dysfunction, oxidative stress, inflammation, cell death and extracellular matrix remodeling. Recently, pyroptosis, a type of programmed cell death related to inflammation, was proven to be activated in DCM. However, the molecular mechanisms underlying pyroptosis in DCM remain elusive. The long non-coding RNA (lncRNA) Kcnq1ot1 participates in many cardiovascular diseases. This study aims to clarify whether Kcnq1ot1 affects cardiac pyroptosis in DCM.

Methods: AC16 cells and primary cardiomyocytes were incubated with 5.5 and 50 mmol/L glucose. Diabetic mice were induced with streptozotocin (STZ). Kcnq1ot1 was silenced both in vitro and in vivo. qRT-PCR was used to detect the expression level of Kcnq1ot1. Immunofluorescence, qRT-PCR and western blot analyses were used to detect the degree of pyroptosis. Echocardiography, hematoxylin and eosin staining, and Masson's trichrome staining were used to detect the cardiac function and morphology in mice. Cell death and function were detected using TUNEL staining, immunofluorescence staining and Ca2+ measurements.

Results: The expression of Kcnq1ot1 was increased in patients with diabetes, high glucose-induced cardiomyocytes and diabetic mouse cardiac tissue. Silencing Kcnq1ot1 alleviated pyroptosis by targeting miR-214-3p and caspase-1. Furthermore, silencing Kcnq1ot1 reduced cell death, cytoskeletal structure abnormalities and calcium overload in vitro and improved cardiac function and morphology in vivo.

Conclusion: Kcnq1ot1 is overexpressed in DCM, and silencing Kcnq1ot1 inhibits pyroptosis by influencing miR-214-3p and caspase-1 expression. We clarified for the first time that Kcnq1ot1 could be a new therapeutic target for DCM.