October 5, 2016

Dual specific phosphatase 12 ameliorates cardiac hypertrophy in response to pressure overload

Structured PICO

Does DUSP12 overexpression or JNK inhibition ameliorate pressure overload-induced cardiac hypertrophy in murine models?

Population

Murine models (DUSP12 knockout and cardiac-specific DUSP12 overexpression) and in vitro cardiomyocytes subjected to pressure overload/hypertrophic stress

Intervention

Cardiac-specific overexpression of DUSP12 or pharmacological inhibition of JNK1/2 activity (SP600125)

Comparator

DUSP12 deficiency (knockout) or wild-type controls

Outcome

Cardiac hypertrophy, fibrosis, and contractile functionsurrogate

DUSP12 protects against pathological cardiac hypertrophy by inhibiting JNK activity, suggesting it may serve as a novel therapeutic target for preventing heart failure.

Abstract

Pathological cardiac hypertrophy is an independent risk factor of heart failure. However, we still lack effective methods to reverse cardiac hypertrophy. DUSP12 is a member of the dual specific phosphatase (DUSP) family, which is characterized by its DUSP activity to dephosphorylate both tyrosine and serine/threonine residues on one substrate. Some DUSPs have been identified as being involved in the regulation of cardiac hypertrophy. However, the role of DUSP12 during pathological cardiac hypertrophy is still unclear. In the present study, we observed a significant decrease in DUSP12 expression in hypertrophic hearts and cardiomyocytes. Using a genetic loss-of-function murine model, we demonstrated that DUSP12 deficiency apparently aggravated pressure overload-induced cardiac hypertrophy and fibrosis as well as impaired cardiac function, whereas cardiac-specific overexpression of DUPS12 was capable of reversing this hypertrophic and fibrotic phenotype and improving contractile function. Furthermore, we demonstrated that JNK1/2 activity but neither ERK1/2 nor p38 activity was increased in the DUSP12 deficient group and decreased in the DUSP12 overexpression group both in vitro and in vivo under hypertrophic stress conditions. Pharmacological inhibition of JNK1/2 activity (SP600125) is capable of reversing the hypertrophic phenotype in DUSP12 knockout (KO) mice. DUSP12 protects against pathological cardiac hypertrophy and related pathologies. This regulatory role of DUSP12 is primarily through c-Jun N-terminal kinase (JNK) inhibition. DUSP12 could be a promising therapeutic target of pathological cardiac hypertrophy. DUSP12 is down-regulated in hypertrophic hearts. An absence of DUSP12 aggravated cardiac hypertrophy, whereas cardiomyocyte-specific DUSP12 overexpression can alleviate this hypertrophic phenotype with improved cardiac function. Further study demonstrated that DUSP12 inhibited JNK activity to attenuate pathological cardiac hypertrophy.

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