Inhibition of HDAC6 Activity Protects Against Endothelial Dysfunction and Atherogenesis in vivo: A Role for HDAC6 Neddylation.

Hyun Woo Sung,Yohei Nomura,Mitsunori Nakano,Mingming Han,Deepesh Pandey

doi:10.3389/fphys.2021.675724

Abstract

We previously reported that histone deacetylase 6 (HDAC6) has an important role in endothelial cell (EC) function in vitro. However, whether HDAC6 plays a role in atherogenesis in vivo and the mechanism(s) that control HDAC6 activity/expression in response to atherogenic stimuli are unclear. The goals of this study were to determine whether HDAC6 inhibitor tubacin attenuates atherogenesis and to elucidate specific molecular mechanism(s) that regulate endothelial HDAC6 expression/activity. We evaluated whether administration of tubacin attenuated or reversed the endothelial dysfunction and atherosclerosis induced in mice by a single intraperitoneal injection of adeno-associated viruses encoding liver-target PCSK9 gain-of-function mutant followed by a high fat diet (HFD) for 18 weeks. Tubacin significantly blunted PCSK9-induced increases in pulse wave velocity (index of vascular stiffness and overall vascular health) that are also seen in atherogenic mice. Furthermore, tubacin protected vessels from defective vasorelaxation, as evaluated by acetylcholine-mediated relaxation using wire myograph. Plaque burden defined by Oil Red O staining was also found to be significantly less in mice that received tubacin than in those that received PCSK9 alone. Inhibition of the NEDDylation pathway with MLN4924, an inhibitor of NEDD8-activating enzyme 1 (NAE1), significantly increased HDAC6 activity in HAECs. Interestingly, HDAC6 expression remained unchanged. Further, HAECs exposed to the atherogenic stimulus oxidized low-density lipoprotein (OxLDL) exhibited enhanced HDAC6 activity, which was attenuated by pretreatment with MLN4924. The HDAC6 NEDDylation molecular pathway might regulate genes related to endothelial control of vasomotor tone, reactivity, and atherosclerosis. Tubacin may represent a novel pharmacologic intervention for atherogenesis and other vasculopathies.

Highlights

The endothelium plays a major role in the regulation of vascular homeostasis by modulating vasomotor tone, inflammation, and growth and migration of vascular smooth muscle cells
To determine whether histone deacetylase 6 (HDAC6) inhibition improves vascular function, we examined the effect of HDAC6 inhibitor tubacin on vascular stiffness in atherogenic mice
To determine whether atheroprotective effects of HDAC6 inhibition involved attenuation of inflammation, we measured whether intracellular adhesion molecules 1 (ICAM1) is attenuated in aortas isolated from control and tubacin treated atherogenic mice

Summary

Introduction

The endothelium plays a major role in the regulation of vascular homeostasis by modulating vasomotor tone, inflammation, and growth and migration of vascular smooth muscle cells. Histone deacetylases (HDACs) have been shown to modulate atherosclerosis and EC shear stress (Choi et al, 2005; Lee et al, 2012). We have identified HDAC2 as a critical contributor to vascular homeostasis and endothelial health and shown that its inhibition leads to impaired vascular relaxation, reduced NO levels, and increased oxidative stress (Pandey et al, 2015). Others have reported that SIRT1, a class III histone deacetylase, decreases acetylation of endothelial NO synthase (eNOS) post-translationally to enhance NO production (Mattagajasingh et al, 2007). Inhibition of SIRT1 increases NADPH oxidase-derived superoxide release, which leads to decreased NO bioavailability and thereby impairs aortic relaxation in rats (Mattagajasingh et al, 2007; Li et al, 2011)

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