MEGF9 prevents lipopolysaccharide-induced cardiac dysfunction through activating AMPK pathway.

Objective: Inflammation and oxidative damage play critical roles in the pathogenesis of sepsis-induced cardiac dysfunction. Multiple EGF-like domains 9 (MEGF9) is essential for cell homeostasis; however, its role and mechanism in sepsis-induced cardiac injury and impairment remain unclear.

Methods: Adenoviral and adeno-associated viral vectors were applied to overexpress or knock down the expression of MEGF9 in vivo and in vitro. To stimulate septic injury, cardiomyocytes and mice were treated lipopolysaccharide (LPS). To clarify the necessity of AMP-activated protein kinase (AMPK), global AMPK knockout mice were used.

Results: We found that MEGF9 expressions were reduced in cardiomyocytes and mice by LPS stimulation. Compared with negative controls, plasma MEGF9 levels were also decreased in septic patients, and negatively correlated with LPS-induced cardiac dysfunction. In addition, MEGF9 overexpression attenuated, while MEGF9 knockdown aggravated LPS-induced inflammation and oxidative damage in vivo and in vitro, thereby regulating LPS-induced cardiac injury and impairment. Mechanistic studies revealed that MEGF9 overexpression alleviated LPS-induced cardiac dysfunction through activating AMPK pathway.

Conclusion: We for the first time demonstrate that MEGF9 prevents LPS-related inflammation, oxidative damage and cardiac injury through activating AMPK pathway, and provide a proof-of-concept for the treatment of LPS-induced cardiac dysfunction by targeting MEGF9.