GATA4 regulates ANF expression synergistically with Sp1 in a cardiac hypertrophy model

Abstract

Cardiac hypertrophy in response to multiple stimuli has important physiological and pathological significances. GATA4 serves as a nuclear integrator of several signalling pathways during cardiac hypertrophy. Sp1 and Sp3 are also reported to be involved in this process. However, the mechanism by which GATA4 acts as a mediator, integrating these ubiquitously expressed transcriptional factors, is poorly understood. We found that the expression of GATA4 and Sp1 was up-regulated in the myocardium of a pressure overload hypertrophy rat model, as well in phenylephrine-induced (PE-induced) hypertrophic growth of neonatal cardiomyocytes. GST pull-down assays demonstrated that GATA4 could interact with Sp1 in vitro. Therefore, we proposed that GATA4 cooperates with Sp1 in regulating ANF expression, as its reactivation is closely linked with hypertrophy. Further studies demonstrated that GATA4 could activate the ANF promoter synergistically with Sp1 through direct interaction. In contrast, Sp3 exhibited antagonistic function, and overexpression of Sp3 repressed the transcriptional synergy between Sp1 and GATA4. We also found that Sp1 alone could activate the ANF promoter in cardiomyocytes, whereas Sp3 exerted negative effects on ANF expression. Bioinformatics analysis revealed novel Sp-binding sites on the ANF promoter. The recruitment of GATA4 and Sp1 on the ANF promoter was enhanced during phenylephrine-mediated hypertrophy, whereas the recruitment of Sp3 was reduced. The phosphorylation of GATA4 by ERK1/2 kinase could enhance the affinity between GATA4 and Sp1. Thus, our findings revealed the critical interaction of GATA4 and Sp1 in modulating ANF expression, indicating their involvement in cardiac hypertrophy.

Gentisic acid attenuates pressure overload‐induced cardiac hypertrophy and fibrosis in mice through inhibition of the ERK1/2 pathway

“…Thus, we have shown that Sp1 and GATA4 are upregulated in response to hypertrophic stimuli both in vitro and in vivo. These findings are consistent with a previous study 32 and similar to those of Azakie et al, 33 who reported that GATA4 and Sp1 protein levels are increased in a neonatal lamb cardiac shunt model of biventricular hypertrophy. These data suggest that the transcription factor activity of GATA4 and Sp1 exacerbates cardiac hypertrophy.…”

Expression of guanylyl cyclase-B (GC-B/NPR2) receptors in normal human fetal pituitaries and human pituitary adenomas implicates a role for C-type natriuretic peptide

“…Both the promoters for ANP (NPPA) and the GC-A receptor (NPR1) have been shown to be regulated by Sp1 (Liang et al 1999, Kumar et al 2010, Hu et al 2011, and we, and others, have indicated a role for Sp1/Sp3 in controlling Nppc transcription in pituitary cell lines (Ohta et al 1993, Thompson et al 2009). The other major regulator of cGMP signaling is the gaseous neurotransmitter, nitric oxide (NO), and both neuronal and endothelial forms of the NO-synthesizing enzyme, NO synthase (NOS1 and NOS3, respectively), are transcriptionally controlled by Sp1 (Kleinert et al 1998, Bachir et al 2003.…”

Cardiomyocyte behavior on biodegradable polyurethane/gold nanocomposite scaffolds under electrical stimulation

“…Primers for atrial naturiuretic factor (ANF), Connexin 43 (Con43), Cardiac troponin I (cTnl; Tro I), cardiac Troponin T type 2 (Tnnt2; Tro II), NK2 homeobox 5 (Nkx2.5), Myocyte enhancer factor 2C (Mef2c) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were designed using the web-based "Primer 3" program. Primers for ß-cardiac myosin heavy chain (β-MHC), natriuretic peptide B (NPPB) and GATA binding protein 4 (GATA 4) were published previously [45,46]; as were the primers for Beta-2-microtubulin (B2M), TATA box binding protein (TBP) [47] and those for 18S ribosomal protein mRNA (18 sr RNA) [48]. The SYBR Green based qPCR mix was purchased from Peqlab (Erlangen, Germany).…”