CaMKII exacerbates heart failure progression by activating class I HDACs

Area of Science:

• Cardiology
• Molecular Biology
• Biochemistry

Background:

• Persistent cardiac Ca2+/calmodulin dependent Kinase II (CaMKII) activation is crucial in heart failure development.
• The precise mechanisms of CaMKII-induced heart failure progression are not fully understood.
• Class I Histone Deacetylases (HDACs) promote pathological cardiac hypertrophy, while class IIa HDACs suppress it.

Purpose of the Study:

• To investigate the role of CaMKII in regulating class I HDACs during heart failure.
• To explore the potential of targeting class I HDACs as a therapeutic strategy for CaMKII-related heart dysfunction.

Main Methods:

• In vitro phosphorylation assays to assess CaMKII's effect on HDAC activity.
• Mass spectrometry to identify phosphorylation sites on HDAC1 and HDAC3.
• Utilized cardiac-specific CaMKIIδC transgenic mice and myocardial infarction models.
• Employed pharmacological inhibitors (Quisinostat, Apicidin, Entinostat, RGFP966) and siRNA to target HDACs.

Main Results:

• CaMKII increases the activity and expression of HDAC1, HDAC2, and HDAC3.
• CaMKII directly phosphorylates HDAC1 and HDAC3, enhancing their activity.
• Inhibition of CaMKII or class I HDACs prevents cardiac myocyte hypertrophy.
• HDAC1 inhibition improved cardiac function and autophagy in a mouse model.

Conclusions:

• CaMKII activation of class I HDACs is a key mechanism in heart failure progression.
• Targeting class I HDACs represents a promising therapeutic approach for heart failure associated with CaMKII hyperactivity.