Involvement of p300/CBP and epigenetic histone acetylation in TGF-β1-mediated gene transcription in mesangial cells

Abstract

Transforming growth factor-β1 (TGF-β1)-induced expression of plasminogen activator inhibitor-1 (PAI-1) and p21 in renal mesangial cells (MCs) plays a major role in glomerulosclerosis and hypertrophy, key events in the pathogenesis of diabetic nephropathy. However, the involvement of histone acetyl transferases (HATs) and histone deacetylases (HDACs) that regulate epigenetic histone lysine acetylation, and their interaction with TGF-β1-responsive transcription factors, are not clear. We evaluated the roles of histone acetylation, specific HATs, and HDACs in TGF-β1-induced gene expression in rat mesangial cells (RMCs) and in glomeruli from diabetic mice. Overexpression of HATs CREB binding protein (CBP) or p300, but not p300/CBP-activating factor, significantly enhanced TGF-β1-induced PAI-1 and p21 mRNA levels as well as transactivation of their promoters in RMCs. Conversely, they were significantly attenuated by HAT domain mutants of CBP and p300 or overexpression of HDAC-1 and HDAC-5. Chromatin immunoprecipitation assays showed that TGF-β1 treatment led to a time-dependent enrichment of histone H3-lysine9/14-acetylation (H3K9/14Ac) and p300/CBP occupancies around Smad and Sp1 binding sites at the PAI-1 and p21 promoters. TGF-β1 also enhanced the interaction of p300 with Smad2/3 and Sp1 and increased Smad2/3 acetylation. High glucose-treated RMCs exhibited increased PAI-1 and p21 levels, and promoter H3K9/14Ac, which were blocked by TGF-β1 antibodies. Furthermore, increased PAI-1 and p21 expression was associated with elevated promoter H3K9/14Ac levels in glomeruli from diabetic mice. Thus TGF-β1-induced PAI-1 and p21 expression involves interaction of p300/CBP with Smads and Sp1, and increased promoter access via p300/CBP-induced H3K9/14Ac. This in turn can augment glomerular dysfunction linked to diabetic nephropathy.

Sirtuin 1: A Target for Kidney Diseases

“…Histone acetylation mediated by histone acetyltransferases promotes an open chromatin formation, which provides binding sites for basal transcription factors and RNA polymerase II to facilitate gene transcription. In contrast, histone deacetylases (HDACs) remove acetyl group from lysine residues of histone, resulting in chromatin compaction and transcription repression (3). In addition, emerging evidence indicates that transcription factors and transcriptional coregulatory proteins are also regulated by acetylation/ deacetylation (3)(4)(5)(6).…”

“…In contrast, histone deacetylases (HDACs) remove acetyl group from lysine residues of histone, resulting in chromatin compaction and transcription repression (3). In addition, emerging evidence indicates that transcription factors and transcriptional coregulatory proteins are also regulated by acetylation/ deacetylation (3)(4)(5)(6). Three classes of mammalian HDACs have been identified, of which silent information regulator 2 (Sir2) or class III HDACs are NAD + -dependent HDACs using coenzyme NAD + for the removal of acetyl groups from lysine residues of histone proteins and nonhistone proteins (7).…”

Epigenomic profiling reveals an association between persistence of DNA methylation and metabolic memory in the DCCT/EDIC type 1 diabetes cohort

“…Several laboratories, including our laboratory, using cell and animal models have suggested roles for key histone PTMs in high glucose (HG)-mediated effects, diabetic complications, and metabolic memory (9,(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31). Histone PTM profiling of vascular and inflammatory cells cultured with HG vs. normal glucose (NG) or WBCs from T1D patients vs. healthy volunteers or T1D patients with complications vs. those without depicted significant PTM differences and candidate differentially methylated or acetylated genes relevant to diabetes or its complications (23,(32)(33)(34).…”

High glucose induces inflammatory reactions and changes in histonemodifying enzymes in rat mesangial cells

“…These pro-fibrotic factors were further enhanced by an HDAC inhibitor, but were suppressed by an HAT inhibitor, confirming the importance of histone acetylation [18]. Increased PAI-1 and p21 expression levels are also associated with elevated promoter H3K9/14Ac levels in glomeruli of diabetic mice [19]. Conversely, the overexpression of HDAC1 and HDAC5 attenuates their expression [19].…”

“…Increased PAI-1 and p21 expression levels are also associated with elevated promoter H3K9/14Ac levels in glomeruli of diabetic mice [19]. Conversely, the overexpression of HDAC1 and HDAC5 attenuates their expression [19].…”