Epigenetic Upregulation of Endogenous VEGF-A Reduces Myocardial Infarct Size in Mice

Abstract

“Epigenetherapy” alters epigenetic status of the targeted chromatin and modifies expression of the endogenous therapeutic gene. In this study we used lentiviral in vivo delivery of small hairpin RNA (shRNA) into hearts in a murine infarction model. shRNA complementary to the promoter of vascular endothelial growth factor (VEGF-A) was able to upregulate endogenous VEGF-A expression. Histological and multiphoton microscope analysis confirmed the therapeutic effect in the transduced hearts. Magnetic resonance imaging (MRI) showed in vivo that the infarct size was significantly reduced in the treatment group 14 days after the epigenetherapy. Importantly, we show that promoter-targeted shRNA upregulates all isoforms of endogenous VEGF-A and that an intact hairpin structure is required for the shRNA activity. In conclusion, regulation of gene expression at the promoter level is a promising new treatment strategy for myocardial infarction and also potentially useful for the upregulation of other endogenous genes.

RNA Activation of the Vascular Endothelial Growth Factor Gene (VEGF) Promoter by Double-Stranded RNA and Hypoxia: Role of Noncoding VEGF Promoter Transcripts

“…tiviral shRNAs used (negative LV-856 or positive LV-451) persistent epigenetic changes occur on the VEGF promoter, including modifications in histone H3K9 methylation and acetylation. In a later report, these shRNAs were successfully applied in an acute therapeutic intervention in a myocardial infarction mice model (31). The identification of such in vivo repressor or inducer of VEGF expression is an obligatory step for future clinical studies.…”

Regulation of VEGF-A Expression in Endothelial Cells by Transcriptional Gene Activation or Transcriptional Gene Silencing: Analysis of Genome Wide Transcriptional Response

“…The role of CREB2 in the regulation of VEGF-A is very interesting and warrants further studies. We have previously found H3K27 to be the most important histone residue for the epigenetic regulation of mouse VEGF-A expression [8,9]. Also, we have shown that CBP/CREB interaction inhibitor abolishes the shRNA-mediated upregulation of VEGF-A.…”

“…CREB, which binds to CRE [23], regulates the H3K27 acetylation by binding CREB binding protein (CBP)/p300 and CREB Regulated Transcription Coactivator (CRTC) [24]. When cells were treated with CBP-CREB interaction inhibitor, the shRNA-mediated VEGF-A upregulation was reduced to the level of shRNA control [9].…”

“…These molecules are complementary to the promoter of mouse VEGF-A gene, and they are known to either increase or decrease VEGF-A expression by causing epigenetic changes in the promoter region as described previously [8,9]. Epigenetic gene regulation is a natural mechanism for altering gene expression during development and adaptation to new situations.…”

Novel Nuclear Biology of Small Non-Coding RNAs

“…When we delivered these shRNAs to ischemic mouse hindlimbs in vivo using lentiviral vectors, we observed increased vascularity in muscles where expression of Vascular Endothelial Growth Factor A (VEGF-A) was upregulated by TGA [6]. In a later study, we analyzed therapeutic potential of shRNA mediated TGA of VEGF-A in a murine myocardial infarction model [7]. In the treated group infarction size was siqnificantly reduced after two weeks of lentiviral injection as analyzed by MRI and histology.…”