The Histone Methyltransferase Inhibitor BIX01294 Enhances the Cardiac Potential of Bone Marrow Cells

Abstract

Bone marrow (BM) has long been considered a potential stem cell source for cardiac repair due to its abundance and accessibility. Although previous investigations have generated cardiomyocytes from BM, yields have been low, and far less than produced from ES or induced pluripotent stem cells (iPSCs). Since differentiation of pluripotent cells is difficult to control, we investigated whether BM cardiac competency could be enhanced without making cells pluripotent. From screens of various molecules that have been shown to assist iPSC production or maintain the ES cell phenotype, we identified the G9a histone methyltransferase inhibitor BIX01294 as a potential reprogramming agent for converting BM cells to a cardiac-competent phenotype. BM cells exposed to BIX01294 displayed significantly elevated expression of brachyury, Mesp1, and islet1, which are genes associated with embryonic cardiac progenitors. In contrast, BIX01294 treatment minimally affected ectodermal, endodermal, and pluripotency gene expression by BM cells. Expression of cardiac-associated genes Nkx2.5, GATA4, Hand1, Hand2, Tbx5, myocardin, and titin was enhanced 114,76, 276,46, 635, 123, and 5-fold in response to the cardiogenic stimulator Wnt11 when BM cells were pretreated with BIX01294. Immunofluorescent analysis demonstrated that BIX01294 exposure allowed for the subsequent display of various muscle proteins within the cells. The effect of BIX01294 on the BM cell phenotype and differentiation potential corresponded to an overall decrease in methylation of histone H3 at lysine9, which is the primary target of G9a histone methyltransferase. In summary, these data suggest that BIX01294 inhibition of chromatin methylation reprograms BM cells to a cardiac-competent progenitor phenotype.

Inhibition of H3K9 Methyltransferase G9a Repressed Cell Proliferation and Induced Autophagy in Neuroblastoma Cells

“…In this study, we investigated the role of G9a in neuroblastoma tumor growth together with BIX01294, which is a specific G9a inhibitor [32]–[34]. We provide experimental evidence supporting the role of G9a in the transcriptional regulation of autophagy in neuroblastoma cells.…”

BIX01294, an inhibitor of histone methyltransferase, induces autophagy-dependent differentiation of glioma stem-like cells

“…Inhibition of G9a activity with BIX01294 or siRNA significantly increased myogenic differentiation37. Bone marrow mesenchymal stem cells differentiated to cardiac-competent progenitors after BIX01294 treatment3839. Combination of small molecule inhibitors, BIX01294 and BayK8644 interfered with reprogramming of Oct4/Klf4-transduced mouse embryonic fibroblast into pluripotent stem cells40.…”

G9a histone methyltransferase inhibitor BIX01294 promotes expansion of adult cardiac progenitor cells without changing their phenotype or differentiation potential

“…In previous studies, we reported that BIX01294 can enhance the cardiac competency of bone marrow cells . As a follow‐up to that earlier finding, we wanted to investigate whether BIX01294 may also have a positive effect on progenitor cells within the heart.…”