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Liganded peroxisome proliferator-activated receptors (PPARs) preserve nuclear histone deacetylase 5 levels in endothelin-treated Sprague-Dawley rat cardiac myocytes.

ABSTRACT: Ligand activation of peroxisome proliferator-activated receptors (PPARs) prevents cardiac myocyte hypertrophy, and we previously reported that diacylglycerol kinase zeta (DGK?) is critically involved. DGK? is an intracellular lipid kinase that catalyzes phosphorylation of diacylglycerol; by attenuating DAG signaling, DGK? suppresses protein kinase C (PKC) and G-protein signaling. Here, we investigated how PPAR-DGK? signaling blocks activation of the hypertrophic gene program. We focused on export of histone deacetylase 5 (HDAC5) from the nucleus, a key event during hypertrophy, since crosstalk occurs between PPARs and other members of the HDAC family. Using cardiac myocytes isolated from Sprague-Dawley rats, we determined that liganded PPARs disrupt endothelin-1 (ET1)-induced nuclear export of HDAC5 in a manner that is dependent on DGK?. When DGK?-mediated PKC inhibition was circumvented using a constitutively-active PKC? mutant, PPARs failed to block ET1-induced nuclear retention of HDAC5. Liganded PPARs also prevented (i) activation of protein kinase D (the downstream effector of PKC), (ii) HDAC5 phosphorylation at 14-3-3 protein chaperone binding sites (serines 259 and 498), and (iii) physical interaction between HDAC5 and 14-3-3, all of which are consistent with blockade of nucleo-cytoplasmic shuttling of HDAC5. Finally, the ability of PPARs to prevent neutralization of HDAC5 activity was associated with transcriptional repression of hypertrophic genes. This occurred by first, reduced MEF2 transcriptional activity and second, augmented deacetylation of histone H3 associated with hypertrophic genes expressing brain natriuretic peptide, ?-myosin heavy chain, skeletal muscle ?-actin, and cardiac muscle ?-actin. Our findings identify spatial regulation of HDAC5 as a target for liganded PPARs, and to our knowledge, are the first to describe a mechanistic role for nuclear DGK? in cardiac myocytes. In conclusion, these results implicate modulation of HDAC5 as a mechanism by which liganded PPARs suppress the hypertrophic gene program.

SUBMITTER: Zhang H

PROVIDER: S-EPMC4267838 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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Liganded peroxisome proliferator-activated receptors (PPARs) preserve nuclear histone deacetylase 5 levels in endothelin-treated Sprague-Dawley rat cardiac myocytes.

Zhang Haining H Shao Zongjun Z Alibin Caroline P CP Acosta Crystal C Anderson Hope D HD

PloS one 20141216 12

Ligand activation of peroxisome proliferator-activated receptors (PPARs) prevents cardiac myocyte hypertrophy, and we previously reported that diacylglycerol kinase zeta (DGKζ) is critically involved. DGKζ is an intracellular lipid kinase that catalyzes phosphorylation of diacylglycerol; by attenuating DAG signaling, DGKζ suppresses protein kinase C (PKC) and G-protein signaling. Here, we investigated how PPAR-DGKζ signaling blocks activation of the hypertrophic gene program. We focused on expor ...[more]

PMID: 25514029

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Project description:BACKGROUND: Megalin is a large endocytic receptor with relevant functions during development and adult life. It is expressed at the apical surface of several epithelial cell types, including proximal tubule cells (PTCs) in the kidney, where it internalizes apolipoproteins, vitamins and hormones with their corresponding carrier proteins and signaling molecules. Despite the important physiological roles of megalin little is known about the regulation of its expression. By analyzing the human megalin promoter, we found three response elements for the peroxisomal proliferator-activated receptor (PPAR). The objective of this study was to test whether megalin expression is regulated by the PPARs. METHODOLOGY/PRINCIPAL FINDINGS: Treatment of epithelial cell lines with PPAR? or PPAR? ligands increased megalin mRNA and protein expression. The stimulation of megalin mRNA expression was blocked by the addition of specific PPAR? or PPAR? antagonists. Furthermore, PPAR bound to three PPAR response elements located in the megalin promoter, as shown by EMSA, and PPAR? and its agonist activated a luciferase construct containing a portion of the megalin promoter and the first response element. Accordingly, the activation of PPAR? and PPAR? enhanced megalin expression in mouse kidney. As previously observed, high concentrations of bovine serum albumin (BSA) decreased megalin in PTCs in vitro; however, PTCs pretreated with PPAR? and PPAR? agonists avoided this BSA-mediated reduction of megalin expression. Finally, we found that megalin expression was significantly inhibited in the PTCs of rats that were injected with BSA to induce tubulointerstitial damage and proteinuria. Treatment of these rats with PPAR? agonists counteracted the reduction in megalin expression and the proteinuria induced by BSA. CONCLUSIONS: PPAR?/? and their agonists positively control megalin expression. This regulation could have an important impact on several megalin-mediated physiological processes and on pathophysiologies such as chronic kidney disease associated with diabetes and hypertension, in which megalin expression is impaired.

Project description:AIMS:Peroxisome proliferator-activated receptor ? (PPAR?) agonists reduce blood pressure and vascular injury in hypertensive rodents. Ppar? inactivation in vascular smooth muscle cells (VSMC) enhances vascular injury. Transgenic mice overexpressing endothelin (ET)-1 selectively in the endothelium (eET-1) exhibit endothelial dysfunction, increased oxidative stress and inflammation. We hypothesized that inactivation of the Ppar? gene in VSMC (smPpar?-/-) would exaggerate ET-1-induced vascular injury. METHODS AND RESULTS:eET-1, smPpar?-/- and eET-1/smPpar?-/- mice were treated with tamoxifen for 5 days and studied 4 weeks later. SBP was higher in eET-1 and unaffected by smPpar? inactivation. Mesenteric artery vasodilatory responses to acetylcholine were impaired only in smPpar?-/-. N(omega)-Nitro-L-arginine methyl ester abrogated relaxation responses, and the Ednra/Ednrb mRNA ratio was decreased in eET-1/smPpar?-/-, which could indicate that nitric oxide production was enhanced by ET-1 stimulation of endothelin type B receptors. Mesenteric artery media/lumen was greater only in eET-1/smPpar?-/-. Mesenteric artery reactive oxygen species increased in smPpar? and were further enhanced in eET-1/smPpar?-/-. Perivascular fat monocyte/macrophage infiltration was higher in eET-1 and smPpar? and increased further in eET-1/smPpar?-/-. Spleen CD11b+ cells were increased in smPpar?-/- and further enhanced in eET-1/smPpar?-/-, whereas Ly-6C(hi) monocytes increased in eET-1 and smPpar?-/- but not in eET-1/smPpar?-/-. Spleen T regulatory lymphocytes increased in smPpar? and decreased in eET-1, and decreased further in eET-1/smPpar?-/-. CONCLUSION:VSMC Ppar? inactivation exaggerates ET-1-induced vascular injury, supporting a protective role for PPAR? in hypertension through modulation of pro-oxidant and proinflammatory pathways. Paradoxically, ET-1 overexpression preserved endothelial function in smPpar?-/- mice, presumably by enhancing nitric oxide through stimulation of endothelin type B receptors.

Dataset Information

Liganded peroxisome proliferator-activated receptors (PPARs) preserve nuclear histone deacetylase 5 levels in endothelin-treated Sprague-Dawley rat cardiac myocytes.

Publications

Liganded peroxisome proliferator-activated receptors (PPARs) preserve nuclear histone deacetylase 5 levels in endothelin-treated Sprague-Dawley rat cardiac myocytes.

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