Epigenetic Histone Modification and Cardiovascular Lineage Programming in Mouse Embryonic Stem Cells Exposed to Laminar Shear Stress

Abstract

Abstract-Experimental evidence indicates that shear stress (SS) exerts a morphogenetic function during cardiac development of mouse and zebrafish embryos. However, the molecular basis for this effect is still elusive. Our previous work described that in adult endothelial cells, SS regulates gene expression by inducing epigenetic modification of histones and activation of transcription complexes bearing acetyltransferase activity. In this study, we evaluated whether SS treatment could epigenetically modify histones and influence cell differentiation in mouse embryonic stem (ES) cells. Cells were exposed to a laminar SS of 10 dyne per cm 2 /s Ϫ1 , or kept in static conditions in the presence or absence of the histone deacetylase inhibitor trichostatin A (TSA). These experiments revealed that SS enhanced lysine acetylation of histone H3 at position 14 (K14), as well as serine phosphorylation at position 10 (S10) and lysine methylation at position 79 (K79), and cooperated with TSA, inducing acetylation of histone H4 and phosphoacetylation of S10 and K14 of histone H3. In addition, ES cells exposed to SS strongly activated transcription from the vascular endothelial growth factor (VEGF) receptor 2 promoter. This effect was paralleled by an early induction of cardiovascular markers, including smooth muscle actin, smooth muscle protein 22-␣, platelet-endothelial cell adhesion molecule-1, VEGF receptor 2, myocyte enhancer factor-2C (MEF2C), and ␣-sarcomeric actin. In this condition, transcription factors MEF2C and Sma/MAD homolog protein 4 could be isolated from SS-treated ES cells complexed with the cAMP response element-binding protein acetyltransferase. These results provide molecular basis for the SS-dependent cardiovascular commitment of mouse ES cells and suggest that laminar flow may be successfully applied for the in vitro production of cardiovascular precursors. (Circ Res. 2005;96:501-508.)

Mechanical modulation of osteochondroprogenitor cell fate

“…The points depicted in the figure represent both primary cells and cells lines, which have been demonstrated to have similar properties. 1 Pa = 10 dyn/cm 2 (after Anderson and Knothe Tate 2007a) [McBeath et al 2004, Meinel et al 2004, Knippenberg et al 2005, David et al 2007, Akimoto et al 2005, Baksh et al 2006, Campbell et al 2006, Takahashi et al 1998, Miyhanishi et al 2006, Hillsley and Frangos 1994, Billotte et al 2001, Klein-Nulend et al 1986, Wong and Carter 1990, Henderson et al 2007, Angele et al 2003, Roelofsen et al 1995, Illi et al 2005]. …”

Cell shape regulates global histone acetylation in human mammary epithelial cells

“…It has been shown that disrupting actomyosin tension generation by inhibiting myosin light chain kinase, RhoA, or Rho-kinase leads to global histone deacetylation, and conversely, increasing actomyosin contractility enhances histone acetylation levels in gastric carcinoma cells [41]. Increasing tension by application of shear stress leads to histone acetylation, chromatin remodeling, and changes in gene expression in endothelial and embryonic stem cells [54,55]. In agreement, experimental and theoretical evidence supports a specific role for the actin cytoskeleton in physically connecting sites of cell adhesion to ECM with the nucleus [51] as well as integrating changes in cell and nuclear shape [56,57].…”

MAP kinases and the control of nuclear events

“…Although consensus MAPK histone phosphorylation sites have not been described in vivo, MAPKs can activate histone-phosphorylating kinases (Cheung et al, 2000;Zhong et al, 2001). For example, ERK1/2 and p38a, -b can provoke changes in chromatin structure (Li et al, 2001;Illi et al, 2005;Schmeck et al, 2005) most likely owing to the activation of downstream kinases such as MSK1/2 (Saccani et al, 2002;Soloaga et al, 2003;Lee et al, 2006a;Vicent et al, 2006) or RSK2 (Cheung et al, 2000) that phosphorylate the N-terminal tail of histones. A surprising recent finding is that MAPKs bind to specific actively transcribed genes, as documented in yeast (Pokholok et al, 2006), reinforcing the idea that MAPKs participate actively in chromatin remodeling, perhaps explaining the observation that MAPKs such as p38a and ERK1/2 bind cellular DNA as judged by the use of chromatin immunoprecipitation assays in mammalian cells (Simone et al, 2004;Vicent et al, 2006).…”