Epigenetic Regulation of Endothelial Lineage Committed Genes in Pro-Angiogenic Hematopoietic and Endothelial Progenitor Cells

Abstract

Rationale: Proangiogenic hematopoietic and endothelial progenitor cells (EPCs) contribute to postnatal neovascularization, but the mechanisms regulating differentiation to the endothelial lineage are unclear.Objective: To elucidate the epigenetic control of endothelial gene expression in proangiogenic cells and EPCs. Methods and Results: Here we demonstrate that the endothelial nitric oxide synthase (eNOS) promoter is epigenetically silenced in proangiogenic cells (early EPCs), CD34؉ cells, and mesoangioblasts by DNA methylation and prominent repressive histone H3K27me3 marks. In order to reverse epigenetic silencing to facilitate endothelial commitment, we used 3-deazaneplanocin A, which inhibits the histone methyltransferase enhancer of zest homolog 2 and, thereby, reduces H3K27me3. 3-Deazaneplanocin A was not sufficient to increase eNOS expression, but the combination of 3-deazaneplanocin A and the histone deacetylase inhibitor Trichostatin A augmented eNOS expression, indicating that the concomitant inhibition of silencing histone modification and enhancement of activating histone modification facilitates eNOS expression. In ischemic tissue, hypoxia plays a role in recruiting progenitor cells. Therefore, we examined the effect of hypoxia on epigenetic modifications. Hypoxia modulated the balance of repressive to active histone marks and increased eNOS mRNA expression. The reduction of repressive H3K27me3 was associated with an increase of the histone demethylase Jmjd3. Silencing of Jmjd3 induced apoptosis and senescence in proangiogenic cells and inhibited hypoxia-mediated up-regulation of eNOS expression in mesoangioblasts. Key Words: Jmjd3 Ⅲ eNOS Ⅲ hypoxia Ⅲ proangiogenic cells E ndothelial or hematopoietic progenitor cells contribute to vascular repair and postnatal neovascularization. Administration of progenitor cells augmented neovascularization and functional recovery after critical ischemia studies. 1 However, the mechanisms underlying the beneficial effect of progenitor cells are unclear, and it is still intensely debated whether endothelial and hematopoietic progenitor cells can undergo differentiation toward the endothelial lineage and incorporate into newly formed blood vessels. 2 The basal mechanisms for endothelial specification and endotheliumspecific gene expression are poorly understood and an endothelial-specific master regulator has yet to be identified. Obviously, many transcription factors such as members of Ets, GATA, and forkhead families play a key role in endothelial gene activation and unique combinational regulation of multiple transcription factors is required for endothelial specification and differentiation. However, many of these transcription factors implicated in vasculogenesis are also expressed in nonendothelial cells like hematopoietic stem cells but are not sufficient to activate endothelial genes. 3 Likewise, expression of the prototypical gene endothelial NO synthase (eNOS) is controlled by a variety of transcription factors such as Sp-1, Ets-1, and YY1, but these tr...

Shifts in podocyte histone H3K27me3 regulate mouse and human glomerular disease

“…In humans with diabetic nephropathy, this coincided with upregulation in the expression of the demethylase UTX, whereas Jmjd3 levels were unaltered. This is interesting, because previous studies have suggested that Jmjd3 expression can be induced by stimuli such as hypoxia and inflammation, which are common features of CKD (9,44). Moreover, although UTX is considered to escape X chromosome inactivation (45), we did not detect a difference in podocyte UTX levels between male and female patients.…”

Endothelial Dysfunction in Children With Obstructive Sleep Apnea Is Associated With Epigenetic Changes in the eNOS Gene

“…[11][12][13][14][15] DNA methylation and histone modifi cations also appear to be involved in the expression of eNOS during endothelial lineage commitment of early endothelial progenitor cells (EPCs). [16][17][18] For instance, the proximal region of the promoter (approximately 740 base pairs upstream from the main transcription start site) was shown to be heavily methylated in early EPCs but not in vascular endothelial cells, an interesting observation considering the role played by EPCs in the vascular phenotype among children with OSA. 19 In addition, repressive trimethyl histone H3 (Lys27) was enriched in the eNOS promoter in early EPCs and treatment with 3-deazaneplanocin A, an S-adenosylhomocysteine hydrolase inhibitor that inhibits Ezh2 and acts as an inhibitor of histone H3 (Lys27) trimethylation, and trichostatin A signifi cantly increased eNOS mRNA expression in these cells.…”

“…19 In addition, repressive trimethyl histone H3 (Lys27) was enriched in the eNOS promoter in early EPCs and treatment with 3-deazaneplanocin A, an S-adenosylhomocysteine hydrolase inhibitor that inhibits Ezh2 and acts as an inhibitor of histone H3 (Lys27) trimethylation, and trichostatin A signifi cantly increased eNOS mRNA expression in these cells. [16][17][18] Furthermore, the potential relevance of the methylation state of the eNOS gene has been recently explored in other contextual settings, such as obesity and bone mineral density. 20,21 In parallel, we have shown that pediatric OSA is associated with discrete increases in CpG site methylation in infl ammatory genes, particularly FOXP3 , suggesting that the presence of sleep-disordered breathing may be conducive to the presence of epigenetic alterations of selected genes.…”

Epigenetics of Arterial Hypertension

“…Встановлено, що промотор eNOS здійс-нює епігенетичний контроль за модифікацією гістонів проангіогенних клітин [27]. Також вивчаються механізми пошкодження під впливом альдостерону гену мішені α-субоди-ниці епітеліального Na + -каналу (ENaC), що визначає зміни транскрипції [28].…”