Dual-specificity phosphatase 14 (Dusp14), an important negative modulator of mitogen-activated protein kinase (MAPK) signaling pathways, has been implicated in inflammatory immune response, cancers, cell differentiation and proliferation. The role of Dusp14 in chronic pressure overload-induced cardiac hypertrophy has not been explored. Here we have shown that Dusp14-/- knockout mice and cardiac-specific Dusp14 transgenic mice were generated and subjected to aortic banding (AB) for 4 weeks. Our results demonstrated that genetic loss of Dusp14 significantly aggravated cardiac hypertrophy, fibrosis, ventricular dilation and dysfunction, whereas transgenic cardiac-specific Dusp14 overexpression significantly attenuated AB-induced cardiac dysfunction and remodeling. In vitro, adenoviral overexpression of constitutive Dusp14 blocked angiotensin II-induced hypertrophic growth of cardiomyocytes, while Dusp14 knockdown led to opposite effects. Mechanistically, excessive phosphorylation of TAK1, P38MAPK and JNK1/2 was evidenced in Dusp14-/- knockout mice post-AB and inactivation of TAK1-P38MAPK and -JNK1/2 signaling using TAK1 inhibitor 5Z-7-ox shares similar antihypertrophic effect as Dusp14 overexpression. Moreover, we show that Dusp14 directly interacted with TAK1. Results from present experiments indicate that Dusp14 protects the heart from AB-induced cardiac hypertrophy and dysfunction possibly through inactivation of TAK1-P38MAPK/-JNK1/2 signaling pathway. Future studies are warranted to test the feasibility of overexpressing Dusp14 as a therapeutic strategy to attenuate cardiac hypertrophy and failure.
Atherosclerosis is a chronic inflammation condition resulting from the interaction between lipoproteins, monocyte-derived macrophages, T lymphocytes, and other cellular elements in the arterial wall. Macrophage-derived foam cells play a key role in both early and advanced stage of atherosclerosis. Previous studies have shown that berberine could inhibit foam cell formation and prevent experimental atherosclerosis. However, its underlying molecular mechanisms have not been fully clarified. In this study, we explored the cholesterol-lowering effects of berberine in macrophage-derived foam cells and investigated its possible mechanisms in prevention and treatment of atherosclerosis. Here, we demonstrated that berberine could inhibit atherosclerosis in apolipoprotein E-deficient mice and induce cholesterol reduction as well as decrease the content of macrophages. Berberine can regulate oxLDL uptake and cholesterol efflux, thus suppresses foam cell formation. Mechanisms study showed that berberine can suppress scavenger receptor expression via inhibiting the activity of AP-1 and upregulate ATP-binding cassette transporter via activating Nrf2/HO-1 signaling in human macrophage. In summary, berberine significantly inhibits atherosclerotic disease development by regulating lipid homeostasis and suppressing macrophage foam cell formation.
This study indicates that sildenafil upregulates MKP-1 expression and promotes degradation of phosphorylation of ERK1/2, which suppresses the proliferation of pulmonary artery smooth muscle cells.
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