Mixed Lineage Kinase 3 (MLK3) Prevents Cardiac Dysfunction and Structural Remodeling with Pressure Overload
Program in Molecular Medicine; Davis Lab
Biochemistry | Cardiovascular Diseases | Cell Biology | Cellular and Molecular Physiology | Enzymes and Coenzymes | Molecular Biology
BACKGROUND: Myocardial hypertrophy is an independent risk factor for heart failure (HF), yet the mechanisms underlying pathological cardiomyocyte growth are incompletely understood. The c-Jun N-terminal kinase (JNK) signaling cascade modulates cardiac hypertrophic remodeling, but the upstream factors regulating myocardial JNK activity remain unclear. In this study we sought to identify JNK-activating molecules as novel regulators of cardiac remodeling in HF.
METHODS AND RESULTS: We investigated Mixed Lineage Kinase 3 (MLK3), a master regulator of upstream JNK-activating kinases, whose role in the remodeling process has not previously been studied. We observed increased MLK3 protein expression in myocardium from patients with nonischemic and hypertrophic cardiomyopathy and in hearts of mice subjected to transverse aortic constriction (TAC). Mice with genetic deletion of MLK3 (MLK3(-/-)) exhibited baseline cardiac hypertrophy with preserved cardiac function. MLK3-/- mice subjected to chronic LV pressure overload (TAC, four weeks) developed worsened cardiac dysfunction and increased LV chamber size compared to MLK3(+/+) littermates (n=8). LV mass, pathological markers of hypertrophy (Nppa, Nppb), and cardiomyocyte size were elevated in MLK3(-/-) TAC hearts. Phosphorylation of JNK, but not other MAPK pathways, was selectively impaired in MLK3(-/-) TAC hearts. In adult rat cardiomyocytes pharmacological MLK3 kinase inhibition using URMC-099 blocked JNK phosphorylation induced by neurohormonal agents and oxidants. Sustained URMC-099 exposure induced cardiomyocyte hypertrophy.
CONCLUSIONS: These data demonstrate MLK3 prevents adverse cardiac remodeling in the setting of pressure overload. Mechanistically, MLK3 activates JNK which in turn opposes cardiomyocyte hypertrophy. These results support modulation of MLK3 as a potential therapeutic approach in HF.
Cardiac Hypertrophy, Cardiomyocyte Hypertrophy, Heart Failure, Mixed Lineage Kinase, c-Jun N-terminal Kinase
DOI of Published Version
Am J Physiol Heart Circ Physiol. 2018 Oct 26. doi: 10.1152/ajpheart.00029.2018. [Epub ahead of print] Link to article on publisher's site
American journal of physiology. Heart and circulatory physiology
Calamaras, Timothy Dean; Baumgartner, Robert A.; Aronovitz, Mark J.; McLaughlin, Angela L.; Tam, Kelly; Richards, Daniel A.; Cooper, Craig W.; Li, Nathan; Baur, Wendy E.; Qiao, Xiaoying; Wang, Guang-Rong; Davis, Roger J.; Kapur, Navin Kumar; Karas, Richard H.; and Blanton, Robert Morris Jr., "Mixed Lineage Kinase 3 (MLK3) Prevents Cardiac Dysfunction and Structural Remodeling with Pressure Overload" (2018). Program in Molecular Medicine Publications and Presentations. 89.