Project description:Epigenetic control of lineage-specific gene expression is essential for cell differentiation, acquisition of specialized functions, and tissue homeostasis. Here, we uncovered a unique epigenetic pathway critical for governing lineage identity in cells presenting milieu-dependent phenotypic modulation in adult organisms, by using vascular smooth muscle cells (SMC) as a model of highly specialized and differentiated cell type retaining phenotypic plasticity. We found that the histone modification H3K4me2 is essential for the maintenance of vascular SMC lineage identity and functions by performing H3K4me2 demethylation selectively on a SMC lineage-specific subset of genes. Removal of H3K4me2 on the myocardin-regulated genes led to a marked loss of contractility and alteration in SMC adaptive response capacities during vascular remodeling. Rather than presenting intrinsic gene activation properties, H3K4me2 serves as a stable preferential hub for the dynamic recruitment of the DNA methylcytosine dioxygenase Ten-Eleven Translocation 2 (TET2). Besides the SMC contractile apparatus, the H3K4me2/TET2 complex controls the expression of miR-145, a central microRNA promoting SMC differentiation and participation in vascular remodeling. Finally, H3K4me2 editing induced a profound loss of SMC lineage identity and gain of plasticity, characterized by the redistribution of H3K4me2 on genes associated with stemness and developmental programs and the greater ability of H3K4me2 edited SMC to transdifferentiate into other lineages. These studies identified H3K4me2 as a central epigenetic mechanism controlling lineage identity and cell-specific specialized functions. Our findings may have broad implications for the understanding of mechanisms controlling multiple plastic cell type behaviors and functions in various pathophysiological processes.
Project description:Epigenetic control of lineage-specific gene expression is essential for cell differentiation, acquisition of specialized functions, and tissue homeostasis. Here, we uncovered a unique epigenetic pathway critical for governing lineage identity in cells presenting milieu-dependent phenotypic modulation in adult organisms, by using vascular smooth muscle cells (SMC) as a model of highly specialized and differentiated cell type retaining phenotypic plasticity. We found that the histone modification H3K4me2 is essential for the maintenance of vascular SMC lineage identity and functions by performing H3K4me2 demethylation selectively on a SMC lineage-specific subset of genes. Removal of H3K4me2 on the myocardin-regulated genes led to a marked loss of contractility and alteration in SMC adaptive response capacities during vascular remodeling. Rather than presenting intrinsic gene activation properties, H3K4me2 serves as a stable preferential hub for the dynamic recruitment of the DNA methylcytosine dioxygenase Ten-Eleven Translocation 2 (TET2). Besides the SMC contractile apparatus, the H3K4me2/TET2 complex controls the expression of miR-145, a central microRNA promoting SMC differentiation and participation in vascular remodeling. Finally, H3K4me2 editing induced a profound loss of SMC lineage identity and gain of plasticity, characterized by the redistribution of H3K4me2 on genes associated with stemness and developmental programs and the greater ability of H3K4me2 edited SMC to transdifferentiate into other lineages. These studies identified H3K4me2 as a central epigenetic mechanism controlling lineage identity and cell-specific specialized functions. Our findings may have broad implications for the understanding of mechanisms controlling multiple plastic cell type behaviors and functions in various pathophysiological processes.
Project description:Epigenetic mechanisms contribute to the regulation of cell differentiation and function. Vascular smooth muscle cells (SMCs) are specialized contractile cells that retain phenotypic plasticity even after differentiation. Here, by performing selective demethylation of histone H3 lysine 4 di-methylation (H3K4me2) at SMC-specific genes, we uncovered that H3K4me2 governs SMC lineage identity. Removal of H3K4me2 via selective editing in cultured vascular SMCs and in murine arterial vasculature led to loss of differentiation and reduced contractility due to impaired recruitment of the DNA methylcytosine dioxygenase TET2. H3K4me2 editing altered SMC adaptative capacities during vascular remodeling due to loss of miR-145 expression. Finally, H3K4me2 editing induced a profound alteration of SMC lineage identity by redistributing H3K4me2 toward genes associated with stemness and developmental programs, thus exacerbating plasticity. Our studies identify the H3K4me2-TET2-miR145 axis as a central epigenetic memory mechanism controlling cell identity and function, whose alteration could contribute to various pathophysiological processes.
Project description:Epigenetic control of lineage-specific gene expression is essential for cell differentiation, acquisition of specialized functions, and tissue homeostasis. Here, we uncovered a unique epigenetic pathway critical for governing lineage identity in cells presenting milieu-dependent phenotypic modulation in adult organisms, by using vascular smooth muscle cells (SMC) as a model of highly specialized and differentiated cell type retaining phenotypic plasticity. We found that the histone modification H3K4me2 is essential for the maintenance of vascular SMC lineage identity and functions by performing H3K4me2 demethylation selectively on a SMC lineage-specific subset of genes. Removal of H3K4me2 on the myocardin-regulated genes led to a marked loss of contractility and alteration in SMC adaptive response capacities during vascular remodeling. Rather than presenting intrinsic gene activation properties, H3K4me2 serves as a stable preferential hub for the dynamic recruitment of the DNA methylcytosine dioxygenase Ten-Eleven Translocation 2 (TET2). Besides the SMC contractile apparatus, the H3K4me2/TET2 complex controls the expression of miR-145, a central microRNA promoting SMC differentiation and participation in vascular remodeling. Finally, H3K4me2 editing induced a profound loss of SMC lineage identity and gain of plasticity, characterized by the redistribution of H3K4me2 on genes associated with stemness and developmental programs and the greater ability of H3K4me2 edited SMC to transdifferentiate into other lineages. These studies identified H3K4me2 as a central epigenetic mechanism controlling lineage identity and cell-specific specialized functions. Our findings may have broad implications for the understanding of mechanisms controlling multiple plastic cell type behaviors and functions in various pathophysiological processes.
Project description:Epigenetic control of lineage-specific gene expression is essential for cell differentiation, acquisition of specialized functions, and tissue homeostasis. Here, we uncovered a unique epigenetic pathway critical for governing lineage identity in cells presenting milieu-dependent phenotypic modulation in adult organisms, by using vascular smooth muscle cells (SMC) as a model of highly specialized and differentiated cell type retaining phenotypic plasticity. We found that the histone modification H3K4me2 is essential for the maintenance of vascular SMC lineage identity and functions by performing H3K4me2 demethylation selectively on a SMC lineage-specific subset of genes. Removal of H3K4me2 on the myocardin-regulated genes led to a marked loss of contractility and alteration in SMC adaptive response capacities during vascular remodeling. Rather than presenting intrinsic gene activation properties, H3K4me2 serves as a stable preferential hub for the dynamic recruitment of the DNA methylcytosine dioxygenase Ten-Eleven Translocation 2 (TET2). Besides the SMC contractile apparatus, the H3K4me2/TET2 complex controls the expression of miR-145, a central microRNA promoting SMC differentiation and participation in vascular remodeling. Finally, H3K4me2 editing induced a profound loss of SMC lineage identity and gain of plasticity, characterized by the redistribution of H3K4me2 on genes associated with stemness and developmental programs and the greater ability of H3K4me2 edited SMC to transdifferentiate into other lineages. These studies identified H3K4me2 as a central epigenetic mechanism controlling lineage identity and cell-specific specialized functions. Our findings may have broad implications for the understanding of mechanisms controlling multiple plastic cell type behaviors and functions in various pathophysiological processes.