Conclusion
These results demonstrated that DUSP1 is a novel anti-inflammatory factor that protects against septic cardiomyopathy by improving FUNDC1-induced mitophagy.
Methods
Lipopolysaccharide was used to induce septic cardiomyopathy in wild-type (WT) and DUSP1 transgenic (DUSP1TG) mice.
Results
Echocardiography revealed that lipopolysaccharide impaired heart function by reducing the cardiac systolic and diastolic capacities of WT mice. Freshly isolated single cardiomyocytes from lipopolysaccharide-treated WT mice also exhibited reduced contractile/relaxation parameters. However, DUSP1 overexpression not only maintained the mechanical properties of cardiomyocytes, but also improved heart performance. Lipopolysaccharide upregulated myocardial inflammatory gene transcription and adhesive factor expression, which increased myocardial neutrophil accumulation and cardiomyocyte apoptosis in WT mice. DUSP1 overexpression inhibited the inflammatory response and therefore promoted cardiomyocyte survival. Lipopolysaccharide disrupted mitochondrial respiration and metabolism in WT cardiomyocytes, but DUSP1 overexpression restored mitochondrial metabolism, maintained the mitochondrial membrane potential and inhibited mitochondrial reactive oxygen species production, possibly by increasing FUN14 domain-containing 1 (FUNDC1)-dependent mitophagy. Silencing of FUNDC1 abolished the protective effects of DUSP1 overexpression on cardiomyocytes and their mitochondria following lipopolysaccharide treatment.