Abstract 14311: Enhanced Cardioprotection by Histone Deacetylase Inhibitor Valproic Acid-preconditioned Human Cord Blood (UCB)-Derived CD34+ Cells
Background UCB CD34+ cells contribute to neo-vascularization into ischemic tissues. Histone Deacetylase Inhibitors enhance CD34+ cells stemness and hematopoietic engraftment potential. In the present study we assessed whether HDACi-preconditioning enhances the ability of these cells to repair the ischemic heart.
Methods and results UCB CD34+ cells were cultured for 7 days into a serum-free medium containing mytogenic cytokines ± valproic acid (VPA, 2.5 mM). VPA treatment reduced proliferation and caused expansion of CD34bright slow-dividing stem cells, as revealed by co-staining with CFSE (CFSEbr/ CD34br VPA vs. C: 25.4±5.9 vs. 1.7±1; n=3; p<0.05, t-test) and Rhodamine 123 (CD34br/Rhlo VPA vs. C: 9.2±1.6% vs. 0.5±0.2% n=4; p<0.05, t-test). Marker analysis by flow cytometry at 7 and 14 days revealed significantly enhanced CD31, CD34, CD90, CD133, CD146, KDR and reduced CD14 expression in VPA vs. C CD34 cells (all p<0.05, n≥4, t-test). A bioplex analysis revealed a significantly increased release of bFGF, GM-CSF, IFNγ, Follistatin, HGF by VPA CD34 cells in culture supernatant (all p<0.05, n≥4, t-test). VPA vs. C CD34+ cells global microRNA and stem cell-specific signatures were assessed by real-time PCR. Unsupervised clustering showed that the two treatments induced discriminated microRNAs and gene expression profiles. Variation in miRNAs (28 in total out of 377 tested) and stem cell-specific transcripts (33 out of 96 tested) were comprised between −12 to 4000 and between −10 to 2900 folds, respectively (C vs. VPA, n=4, p<0.05, t-test). VPA and C CD34 cells were injected (1.5x105/mouse) in the border zone of infarcted hearts at 15′ after coronary artery ligation in SCIDbeige mice. Compared to CD34 C, CD34 VPA cells significantly reduced mortality of mice at 28 days (CD34 VPA vs. C survival rate 80% vs 47%, p=0.02, n≥13, X2 test) and infarct size (32.3±3.6% vs. 41.9±1.8%; CD34 C vs. VPA; n≥9; p<0.05, t-test). By contrast, echo and MRI analyses showed a similarly significant EF increase and LVEDV and LVESV reduction by VPA and C CD34 cells, compared to saline injected mice.
Conclusions Our results suggest that VPA preconditioning induces global changes in UCB CD34+ cells gene expression that is associated with enhanced cardioprotection.
- © 2010 by American Heart Association, Inc.