权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Role of force regulated nuclear structure in expression of osteogenesis

力调节核结构在成骨表达中的作用

基本信息

批准号：
10632101
负责人：
Janet E Rubin
金额：
$ 45.78万
依托单位：
UNIV OF NORTH CAROLINA CHAPEL HILL
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-05-01 至 2025-04-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10632101
关键词：
Actins Address Affect Architecture Biomechanics Bone Marrow Cell Lineage Cell Nucleus Cells Chromatin Cytoplasm Cytoskeleton DNA DNA Repair Data EZH2 gene Epigenetic Process Euchromatin Exercise F-Actin Focal Adhesions Gene Activation Gene Expression Gene Silencing Gene Targeting Genes Genome Heterochromatin Lamin B1 Lamins Link Marrow Measures Mechanics Mediating Mesenchymal Mesenchymal Stem Cells Modeling Nature Nuclear Nuclear Envelope Nuclear Import Nuclear Pore Nuclear Structure Nuclear Translocation Osteoblasts Osteogenesis PPAR gamma Physical condensation Polymers Positioning Attribute Proliferating Publishing Regulator Genes Regulatory Pathway Role Signal Induction Signal Pathway Signal Transduction Small Interfering RNA Stimulus Stress Stromal Cells Structure Testing Variant beta catenin bone bone marrow mesenchymal stem cell epigenetic regulation experience histone methylation inhibitor knock-down lipid biosynthesis loss of function mechanical force mechanical stimulus novel nuclear transfer osteogenic polymerization prevent programs promoter response stem stem cell differentiation stem cell fate stem cells stemness transcription factor transcriptome transcriptome sequencing

项目摘要

Abstract: Role of force regulated nuclear structure in expression of osteogenesis Bone marrow mesenchymal stem cells (MSC) exist in a multipotential state, where osteogenic and adipogenic genomes are silenced in heterochromatin at the inner nuclear leaflet. Activating the osteogenic differentiation program involves multiple regulatory factors, including physical force, which is generated in the marrow space during dynamic exercise. MSC experience mechanical force through their cytoskeletal attachments to substrate, inducing signaling that alters gene expression. We showed that intranuclear actin structures are affected by changes in the cytoplasmic cytoskeleton, and direct changes in intranuclear actin due to knock down of nuclear restricted mDia2 (preventing intranuclear actin polymerization) exert profound regulatory control on gene expression. Further, although both dynamic and static mechanical force activate RhoA to control formation of the actin cytoskeleton, the nature of these forces appear to have widely variant effects on gene expression – dynamic force inhibits adipogenesis and promotes multipotentiality, while static force is associated with osteogenesis. Dynamic versus static applications may affect gene expression through generating different forces on the nucleus, affecting nuclear structure and nuclear access of the mechanoresponders, Yap and β-catenin. We here hypothesize that nuclear structure, modified by force activated actin polymerization, contributes to selective MSC differentiation and fate. To address this hypothesis, we propose to define how cellular actin structure resulting from dynamic or static mechanical force differentially regulate nuclear architecture and gene expression. In SA1 we will find if dynamic and static strain differentially modify nuclear architecture (F-actin and lamin structure, nucleoli size and spacing, cell and nuclear stiffness and FISH localization of Runx2). Our data shows that loss of intranuclear actin polymerization decreases lamin B1 at the inner nuclear leaflet, thus we will find if force alters osteogenic gene silencing through lamins, and if alterations in formin mDia2 or laminB1 modulate heterochromatization of the osteogenic genome. In SA2 we will ask if dynamic and static force differentially regulate nuclear entry of Yap or β-catenin, and relate cytoskeletal stress transfer to the nuclear membrane to changes in nuclear access of these molecules. Unbiased RNAseq will allow us to compare gene expression after dynamic vs static force and ask if nuclear Yap and β- catenin are critical. Lastly in SA3 we determine if intranuclear actin structure directly controls access to the osteogenic genome. We will define nuclear structure after mDia2 knock down (decrease intranuclear F-actin, induces osteogenesis), mDia1 knock down (decreasing cytoplasmic F-actin) and altering secondary actin branching (induces adipogenesis). In these conditions we will relate nuclear structure to activation of Runx2 and PPARγ cistromes. Upon completion of our objectives we will be able to establish how mechanical forces and nuclear actin polymerization control epigenetic induction of osteogenesis and regulate nuclear transfer of YAP and β-catenin.

摘要：力调控核结构在成骨过程中的作用