Journal
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Volume 111, Issue 48, Pages E5178-E5186Publisher
NATL ACAD SCIENCES
DOI: 10.1073/pnas.1415589111
Keywords
autophagy; proteotoxicity; heart; alphaB-crystallin; HDAC6
Categories
Funding
- National Institutes of Health (NIH) [P01HL69779, P01HL059408, R01HL05924, R011062927]
- Le Fondation Leducq
- NIH [F32 HL112558, T32 HL007382, HL116848, AG043822]
- American Heart Association postdoctoral fellowship
- American Heart Association [12POST10680000]
- STFC [ST/K000853/1] Funding Source: UKRI
- NATIONAL HEART, LUNG, AND BLOOD INSTITUTE [F32HL112558, T32HL007171, T32HL007382, F32HL124893, R01HL116848, P01HL069779, P01HL059408] Funding Source: NIH RePORTER
- NATIONAL INSTITUTE ON AGING [R21AG043822] Funding Source: NIH RePORTER
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Proteinopathy causes cardiac disease, remodeling, and heart failure but the pathological mechanisms remain obscure. Mutated alpha B-crystallin (CryAB(R120G)), when expressed only in cardiomyocytes in transgenic (TG) mice, causes desmin-related cardiomyopathy, a protein conformational disorder. The disease is characterized by the accumulation of toxic misfolded protein species that present as perinuclear aggregates known as aggresomes. Previously, we have used the CryAB(R120G) model to determine the underlying processes that result in these pathologic accumulations and to explore potential therapeutic windows that might be used to decrease proteotoxicity. We noted that total ventricular protein is hypoacetylated while hyperacetylation of alpha-tubulin, a substrate of histone deacetylase 6 (HDAC6) occurs. HDAC6 has critical roles in protein trafficking and autophagy, but its function in the heart is obscure. Here, we test the hypothesis that tubulin acetylation is an adaptive process in cardiomyocytes. By modulating HDAC6 levels and/or activity genetically and pharmacologically, we determined the effects of tubulin acetylation on aggregate formation in CryAB(R120G) cardiomyocytes. Increasing HDAC6 accelerated aggregate formation, whereas siRNA-mediated knockdown or pharmacological inhibition ameliorated the process. HDAC inhibition in vivo induced tubulin hyperacetylation in CryAB(R120G) TG hearts, which prevented aggregate formation and significantly improved cardiac function. HDAC6 inhibition also increased autophagic flux in cardiomyocytes, and increased autophagy in the diseased heart correlated with increased tubulin acetylation, suggesting that autophagy induction might underlie the observed cardioprotection. Taken together, our data suggest a mechanistic link between tubulin hyperacetylation and autophagy induction and points to HDAC6 as a viable therapeutic target in cardiovascular disease.
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