Pulsatile Flow Increases METTL14-induced m6A modification and attenuates septic cardiomyopathy: an experimental study.

Abstract

Septic cardiomyopathy is a sepsis-mediated cardiovascular complication with severe microcirculatory malperfusion. Emerging evidence has highlighted the protective effects of pulsatile flow in case of microcirculatory disturbance, yet the underlying mechanisms are still elusive. The objective of this study was to investigate the mechanisms of N6-methyladenosine (m6A) modification in the alleviation of septic cardiomyopathy associated with extracorporeal membrane oxygenation (ECMO)-generated pulsatile flow. Rat model with septic cardiomyopathy was established and was supported under ECMO either with pulsatile or non-pulsatile flow. Peripheral perfusion index (PPI) and cardiac function parameters were measured using ultrasonography. Dot blot assay was applied to examine the m6A level, while qRT-PCR, Western blot, immunofluorescence, and immunohistochemistry were used to measure the expressions of related genes. RNA immunoprecipitation assay was performed to validate the interaction between molecules. The ECMO-generated pulsatile flow significantly elevates microcirculatory PPI, improves myocardial function, protects the endothelium, and prolongs survival in rat models with septic cardiomyopathy. The pulsatile flow mediates the METTL14-mediated m6A modification to zonula occludens- (ZO-) 1 mRNA which stabilizes the ZO-1 mRNA depending on the presence of YTHDF2. The pulsatile flow suppresses the PI3K-Akt signaling pathway, of which the downstream molecule Foxo1, a negative transcription factor of METTL14, binds to the METTL14 promoter and inhibits the METTL14-induced m6A modification. The ECMO-generated pulsatile flow increases METTL14-induced m6A modification in ZO-1 and attenuates the progression of septic cardiomyopathy, suggesting that pulsatility might be a new therapeutic strategy in septic cardiomyopathy by alleviating microcirculatory disturbance.