Exosomal microRNA-194 causes cardiac injury and mitochondrial dysfunction in obese mice

Area of Science:

• Cardiovascular Biology
• Metabolic Disease Research
• Molecular Medicine

Background:

• Obesity significantly increases cardiovascular risks, yet the specific circulating factors impacting cardiac function remain incompletely understood.
• MicroRNAs (miRNAs), particularly hepatic-enriched ones like miR-194, are implicated in metabolic and cardiovascular pathophysiology.

Purpose of the Study:

• To investigate the pathophysiological role of circulating exosomal microRNA-194 (miR-194) in obesity-related cardiomyopathy.
• To explore the potential of miR-194 as a therapeutic target for cardiac dysfunction in obesity.

Main Methods:

• Measured circulating exosomal miR-194 levels in lean and obese human subjects, correlating them with cardiac parameters.
• Utilized miR-194 sponge technology in mouse cardiomyocytes and in vivo models of obesity-related cardiomyopathy to assess functional impacts.
• Assessed mitochondrial activity, including ATP production, oxygen consumption, and complex I activity, in response to miR-194 manipulation.

Main Results:

• Circulating exosomal miR-194 levels were significantly upregulated in obese individuals and correlated with impaired cardiac function (ejection fraction, NT-proBNP).
• In vitro, exosomes from obese mice reduced myocyte mitochondrial activity, an effect attenuated by miR-194 sponge intervention.
• In vivo, high-fat diet-induced cardiac dysfunction and mitochondrial impairment in mice were ameliorated by miR-194 sponge administration.

Conclusions:

• Circulating exosomal miR-194 is a potential biomarker for obesity-related cardiac dysfunction in humans.
• Targeting miR-194, for example, using miR-194 sponge, demonstrates therapeutic potential for mitigating obesity-mediated cardiomyopathy.