Hippo signaling and histone methylation control cardiomyocyte cell cycle re-entry through distinct transcriptional pathways

Abstract

Aims Accumulating data demonstrates that new adult cardiomyocytes (CMs) are generated throughout life from pre-existing CMs, although the absolute magnitude of CM self-renewal is very low. Modifying epigenetic histone modifications or activating the Hippo-Yap pathway have been shown to promote adult CM cycling and proliferation. Whether these interventions work through common pathways or act independently is unknown. For the first time we have determined whether lysine demethylase 4D (KDM4D)-mediated CM-specific H3K9 demethylation and Hippo pathways inhibition have additive or redundant roles in promoting CM cell cycle re-entry. Methods and results We found that activating Yap1 in cultured neonatal rat ventricular myocytes (NRVM) through overexpressing Hippo pathway inhibitor, miR-199, preferentially increased S-phase CMs, while H3K9me3 demethylase KDM4D preferentially increased G2/M markers in CMs. Together KDM4D and miR-199 further increased total cell number of NRVMs in culture. Inhibition of Hippo signaling via knock-down of Salvador Family WW Domain Containing Protein 1 (Sav1) also led to S-phase reactivation and additional cell cycle re-entry was seen when combined with KDM4D overexpression. Inducible activating KDM4D (iKDM4D) in adult transgenic mice together with shRNA mediated knock-down of Sav1 (iKDM4D+Sav1-sh) resulted in a significant increase in cycling CMs compared to either intervention alone. KDM4D preferentially induced expression of genes regulating late (G2/M) phases of the cell cycle, while miR-199 and si-Sav1 preferentially up-regulated genes involved in G1/S phase. KDM4D upregulated E2F1 and FoxM1 expression, whereas miR-199 and si-Sav1 induced Myc. Using transgenic mice over-expressing KDM4D together with Myc, we demonstrated that KDM4D/Myc significantly increased CM cell cycling but did not affect cardiac function. Conclusions KDM4D effects on CM cell cycle activity are additive with the Hippo-Yap1 pathway and appear to preferentially regulate different cell cycle regulators. This may have important implications for strategies that target cardiac regeneration in treating heart disease

Lysine-Specific Demethylase 4D Is Critical for the Regulation of the Cell Cycle and Antioxidant Capacity in Goat Fibroblast Cells

“…In addition, the protein expression of CCND1 and PCNA also confirmed the above results. Previously, there was evidence which demonstrated that Kdm4d could regulate adult cardiomyocyte cycling and proliferation by activating different cell cycle regulators [31], consistent with our present results. These findings, and our results, indicate that the dysregulation of Kdm4d affects cell proliferation and the cell cycle.…”

Histone Modification of Osteogenesis Related Genes Triggered by Substrate Topography Promotes Human Mesenchymal Stem Cell Differentiation

“…81 The nuclear transportation and activation of YAP/TAZ can cause histone acetylation by the related lysine acetyltransferases CBP and p300. 82 Despite the fact that HIPPO pathway or YAP mediated alterations in chromatin accessibility have received great attention in recent studies, 83,84 it remains unclear whether active YAP can facilitate histone modifications at specific differentiation gene promoters in response to topographical or mechanical cues. 85−87 Here, we hypothesize that YAP, together with other nuclear proteins, may regulate histone modification and expression of differentiation related genes in the mechanotransduction processes.…”

“…Despite the fact that HIPPO pathway or YAP mediated alterations in chromatin accessibility have received great attention in recent studies, , it remains unclear whether active YAP can facilitate histone modifications at specific differentiation gene promoters in response to topographical or mechanical cues. − …”

Dynamic Visualization of DNA Methylation in Cell Cycle Genes during iPSC Cardiac Differentiation

“…We also postulate that some genes conserved for various stage of cell functions in different cell types have multiple regulatory mechanisms to fine tune gene expression, such as by microRNA, 9 and epigenetic histone modifications. 20,21 It is worth noting that Cdk1 itself can affect histone epigenetic landscape as shown in mouse embryonic stem cells. 22 The GMR reporter system can be used with both live cell reporters to decipher the intricate cellular processes such as lineage 13 specification and tracking (e.g., cardiomyocyte) and phenotype (e.g., myocyte maturity or cell cycle/proliferation activities) and functions (e.g., myocyte electrical and contractile activities).…”