DJ-1 regulates the expression of renal (pro)renin receptor via reactive oxygen species-mediated epigenetic modification

Highlights

• Deficiency of DJ-1 elevates the expressions of renal PRR.

• ROS potently induces epigenetic modifications at PRR promoter.

• DJ-1 controls renal PRR expression via H₂O₂-mediated epigenetic modification.

• Deficiency of DJ-1 elevates the expressions of renal fibrotic genes.

• DJ-1 may be a key molecule in the acceleration of renal pathogenesis via PRR regulation.

Abstract

Background

DJ-1 protein plays multifunctional roles including transcriptional regulation and scavenging oxidative stress; thus, it may be associated with the development of renal disorders. We investigated whether DJ-1 protein regulates the expression of (pro)renin receptor (PRR), a newly identified member of renin–angiotensin system.

Methods

The levels of mRNA and protein were determined by real-time PCR and western blot, respectively. H₂O₂ production was tested by using fluorescence probe. Histone modification was determined by chromatin immunoprecipitation.

Results

The expression of PRR was significantly higher in the kidney from DJ-1 knockout mice (DJ-1^−/−) compared with wild-type mice (DJ-1^+/+). Histone deacetylase 1 recruitment at the PRR promoter was lower, and histone H3 acetylation and RNA polymerase II recruitment were higher in DJ-1^−/− than in DJ-1^+/+. Knockdown or inhibition of histone deacetylase 1 restored PRR expression in mesangial cells from DJ-1^+/+. H₂O₂ production was greater in DJ-1^−/− cells compared with DJ-1^+/+ cells. These changes in PRR expression and epigenetic modification in DJ-1^−/− cells were induced by H₂O₂ treatment and reversed completely by addition of an antioxidant reagent. Prorenin-stimulated ERK1/2 phosphorylation was greater in DJ-1^−/− than in DJ-1^+/+ cells and this was inhibited by a PRR-inhibitory peptide, and by AT1 and AT2 receptor inhibitors. The expression of renal fibrotic genes was higher in DJ-1^−/− than in DJ-1^+/+ cells and decreased in PRR-knockdown DJ-1^−/− cells.

Conclusions

We conclude that DJ-1 protein regulates the expression of renal PRR through H₂O₂-mediated epigenetic modification.

General significance

We suggest that renal DJ-1 protein may be an important molecule in the acceleration of renal pathogenesis through PRR regulation.

Introduction

The renin–angiotensin system (RAS) plays a critical role in the initiation and progression of renal disease [1]. The (pro)renin receptor (PRR), a newly identified member of the RAS, is a single transmembrane receptor for renin and its precursor prorenin [2]. Binding of renin and prorenin to the PRR leads to two distinct reactions: it facilitates the catalytic activity of renin or prorenin in converting angiotensinogen to angiotensin (Ang) I and it directly transmits its signals into the intracellular space [3], [4]. Both pathways consequently initiate the activation of extracellular signal-regulated kinase (ERK) 1/2, in Ang II type (AT) 1 receptor-dependent and/or -independent manner [5]. PRR-activated ERK1/2 also participates in the production of the fibrotic factors in renal mesangial cells stimulated with prorenin [6], [7], [8]. Moreover, the overexpression of PRR in animals showed renal pathogenesis, such as glomerulosclerosis, fibrosis, or proteinuria [9], [10]. Although previous reports have considered a pivotal role of the PRR in renal pathogenesis, a regulatory mechanism of the PRR by reactive oxygen species (ROS) or antioxidant proteins, e.g. DJ-1 protein, has not been elucidated.

DJ-1 was described originally as an oncogene that transforms NIH3T3 cells in cooperation with H-ras [11] and has also been found to be a causative gene for familial Parkinson's disease [12]. DJ-1 is a multifunctional antioxidant protein that scavenges ROS [13]. It is commonly accepted that DJ-1 deficiency results in the elevation of ROS in a variety of cells including renal, vascular, and immune cells [14], [15], [16]. Previous studies have reported that ROS in the absence of DJ-1 contributes to diverse pathophysiological events including the overexpression of genes [14], [17], [18], [19]. In addition, DJ-1 regulates transcriptional activities of several genes by directly interacting with histone deacetylase (HDAC) [20], [21]. Thus, these data suggest that DJ-1 may be involved in the acceleration of renal diseases resulting from the ROS-mediated transcriptional regulation.

Epigenetic modifications such as acetylation, methylation, ubiquitination, and phosphorylation of histone protein are associated with the development of diverse diseases [22]. Acetylation of histone proteins is regulated mainly by the balance between HDAC and histone acetyltransferase (HAT) [23]. The regulation of HDAC contributes to nuclear and cellular processes such as gene expression, development, cell cycle, and migration [24]. Therefore, clarifying the epigenetic roles of DJ-1 is important if we are to understand the acceleration of pathogenesis in the kidney.

In the present study, we tested the hypothesis that DJ-1 deletion is linked to the upregulation of the renal PRR, which consequently results in renal pathogenesis. We monitored the epigenetic regulation of the PRR in mesangial cells from DJ-1 knockout (DJ-1^−/−) and their wild-type mice (DJ-1^+/+) and identified the possible implications of DJ-1 protein in renal diseases.