Ezh2‐dependent H3K27me3 modification dynamically regulates vitamin D3‐dependent epigenetic control of CYP24A1 gene expression in osteoblastic cells

Abstract

Epigenetic control is critical for the regulation of gene transcription in mammalian cells. Among the most important epigenetic mechanisms are those associated with posttranslational modifications of chromosomal histone proteins, which modulate chromatin structure and increased accessibility of promoter regulatory elements for competency to support transcription. A critical histone mark is trimethylation of histone H3 at lysine residue 27 (H3K27me3), which is mediated by Ezh2, the catalytic subunit of the polycomb group complex PRC2 to repress transcription. Treatment of cells with the active vitamin D metabolite 1,25(OH)2D3, results in transcriptional activation of the CYP24A1 gene, which encodes a 24‐hydroxylase enzyme, that is, essential for physiological control of vitamin D3 levels. We report that the Ezh2‐mediated deposition of H3K27me3 at the CYP24A1 gene promoter is a requisite regulatory component during transcriptional silencing of this gene in osteoblastic cells in the absence of 1,25(OH)2D3. 1,25(OH)2D3 dependent transcriptional activation of the CYP24A1 gene is accompanied by a rapid release of Ezh2 from the promoter, together with the binding of the H3K27me3‐specific demethylase Utx/Kdm6a and thereby subsequent erasing of the H3K27me3 mark. Importantly, we find that these changes in H3K27me3 enrichment at the CYP24A1 gene promoter are highly dynamic, as this modification is rapidly reacquired following the withdrawal of 1,25(OH)2D3.

Vitamin D and Bone: A Story of Endocrine and Auto/Paracrine Action in Osteoblasts

“…The first step in the degradation cascade of 1α,25-OH 2 D 3 is hydroxylation at the C-24 position by 24-hydroxylase (CYP24A1) [ 137 ]. CYP24A1 is expressed in all vitamin D target cells, and its expression is very rapidly and strongly increased after 1α,25-OH 2 D 3 binding to VDRs [ 138 , 139 , 140 , 141 ]. The VDR level is tightly linked to the induction of CYP24A1 expression and 24-hydroxylase activity and, consequently, degradation of 1α,25-OH 2 D 3 .…”

1,25(OH)2D3 ameliorates doxorubicin‑induced cardiomyopathy by inhibiting the NLRP3 inflammasome and oxidative stress

“…1, 25(OH) 2 D 3 treatment affects histone modification levels in NLRP3 and Nrf2 promoters in DOX-induced cardiomyopathy. Previous studies have reported that 1,25(OH) 2 D 3 can affect histone modifications to regulate downstream target gene expression and impact transcriptional regulation (37). To clarify the effect of 1,25(OH) 2 D 3 on the level of histone modification in the NLRP3 promoter, ChIP assay was used to assess the levels of H3K4 (H3K4me 3 ) and H3K27 (H3K27me 3 ) trimethylation, in addition to H2AK119 monoubiquitination (H2AK119Ub), in the NLRP3 promoter region.…”

Protein arginine methyltransferases PRMT1, PRMT4/CARM1 and PRMT5 have distinct functions in control of osteoblast differentiation

“…Chromatin organization is dynamically altered by histone post-translational modifications (PTMs) that mediate epigenetic regulation of osteogenic lineage differentiation and osteoblast maturation ( van Wijnen and Westendorf, 2019 ). We and others have identified multiple enzymes expressed in osteogenic cells that mediate or recognize lysine methylation ( Dashti et al, 2023 ; Dudakovic et al, 2016 ; Dudakovic et al, 2020 ; Galvan et al, 2021 ; Khani et al, 2017 ; Moena et al, 2020a ; Rojas et al, 2019 ; van Wijnen et al, 2021 ), demethylation ( Dudakovic et al, 2017 ; Rojas et al, 2015 ; Rummukainen et al, 2022 ) or acetylation of histones ( Dudakovic et al, 2013 ; Galea et al, 2020 ; Paradise et al, 2020 ; Paradise et al, 2022 ; Shen et al, 2003 ; Sierra et al, 2003 ), as well as DNA methylation and hydroxylation ( Thaler et al, 2022 ). These epigenetic regulatory enzymes can induce modifications on different amino acids located on histone tails including lysines (K), arginines (R), and serines (S) ( Tan et al, 2011 ).…”