Cardiomyocyte specific plin5 over expression

Presence of ectopic lipid droplets (LDs) in cardiac muscle is associated to lipotoxicity and tissue dysfunction. However, presence of LDs in heart is also observed in physiological conditions, such as at times when cellular energy needs and energy production from mitochondria fatty acid (FA) -oxidation are high (fasting). This suggests that development of tissue lipotoxicity and dysfunction is not simply due to the presence of LDs in cardiac muscle but due at least in part to alterations in LD function. To examine the function of cardiac LDs, we obtained transgenic mice with heart-specific plin5 over-expression (MHC-plin5), a member of the perilipin protein family. Hearts from MHC-plin5 mice expressed at least 4-fold higher levels of plin5 and exhibit a 3.5- fold increase in triglyceride content versus non-transgenic littermate. Chronic cardiac excess of LDs was found to result in mild heart dysfunction with decreased expression of PPAR target genes, decreased mitochondria function and left ventricular concentric hypertrophia. Lack of more severe heart function complications may have been prevented by a strong increased expression of oxidative induced genes via NF-E2-related factor 2 anti-oxidative pathway. Perilipin 5 regulates the formation and stabilization of cardiac LDs, and promotes cardiac steatosis without major heart function impairment.

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Wang H, Sreenivasan U, Gong DW, O'Connell KA, Dabkowski ER, Hecker PA, Ionica N, Konig M, Mahurkar A, Sun Y, Stanley WC, Sztalryd C