The DNA methylome-based regulation of functional beta-cell mass

基于 DNA 甲基化组的功能性 β 细胞群调节

基本信息

批准号：
10647908
负责人：
Guoqiang Gu
金额：
$ 44.31万
依托单位：
VANDERBILT UNIVERSITY
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：
2020-07-01 至 2025-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10647908
关键词：
Acute Address Affect Age Months Aging Attenuated Beta Cell Birth Cell Differentiation process Cell Lineage Cell Proliferation Cell physiology Cells DNA DNA Methylation DNA Modification Methylases DNA Sequence Alteration DNMT3a Darkness Data Derivation procedure Development Diabetes Mellitus Diet Dioxygenases Disease Down-Regulation Embryo Embryonic Development Endocrine Enhancers Enzymes Epigenetic Process Exposure to Future Gene Expression Genes Genetic Genetic Polymorphism Glucose Goals Human Hyperglycemia Hypoglycemia Immunocompromised Host Insulin Resistance Islet Cell Link Maintenance Metabolic stress Methylation Modeling Molecular Mus Non-Insulin-Dependent Diabetes Mellitus Nutrient Pancreas Pattern Physiological Physiology Positioning Attribute Predisposition Process Production Proliferating Protein-Restricted Diet Publishing Regulation Repression Risk Factors Role Sentinel Specific qualifier value Stress Testing Text allotransplant combinatorial demethylation dosage fitness genomic locus improved innovation insulin secretion islet stem cells methylome mother nutrition offspring postnatal prenatal exposure prevent progenitor programs stem cells synaptotagmin VII transcription factor transcriptome

项目摘要

Insufficient functional β-cell mass can cause type 2 diabetes (T2D). This application will elucidate how the DNA methylomes in embryonic multipotent pancreatic progenitor cells (mPPCs) pre-determine this mass. During embryogenesis, mPPCs activate pro-endocrine transcription factor (TF) Ngn3 to give rise to endocrine progenitor cells (EPCs), from which β cells are derived. DNA methylation is a relatively stable repressive mark that is laid down by several enzymes including DNA methyl-transferase 1 (Dnmt1). DNMT1 polymorphisms are associated with attenuated β-cell function and human T2D. We show that fetal exposure to maternal low-protein diet, known to compromise functional β-cell mass, enhances Dnmt1 expression in mouse mPPCs. We recently published that both mPPC and EPC pools can be split into subsets that carry different DNA methylation levels at likely instructive gene enhancers, which can bias islet-cell fate choice. Moreover, higher Dnmt1 expression in mPPCs/EPCs favors β-cell differentiation; yet EPC differentiation toward islet cells involves a rapid and substantial downregulation of Dnmt1 and concordant de-methylation in putative enhancers of genes that regulate β-cell proliferation and function (referred to as fitness). The latter includes Synaptotagmin 7 (Syt7), a gene that promotes glucose-stimulated insulin secretion. Our model is that the methylomes in mPPCs can influence the evolving methylomes in their descendant EPCs and β cells. Thus, mPPCs with distinct methylomes can give rise to β-cell subsets with different fitness by pre-setting the expression levels of genes that will be activated later for high β-cell fitness qualities. Perturbing the early-stage methylomes, by changed Dnmt1 expression and/or maternal diet manipulation, will shift the portions of β-cell subsets and consequently the functional β-cell mass and the susceptibility to T2D. Consistent with this model, we showed that a portion (~55%) of β cells derived from a subset of Ngn3+ EPCs that co-express TF Myt1 (i.e., Myt1+Ngn3+ or “M+N+”) has higher postnatal fitness than those from M-N+ cells under normal physiology. Here, we will first define the fitness of M+N+ or M-N+ progenitor-derived β-cell subsets under metabolic stresses such as aging, hyperglycemia, or insulin resistance to elucidate their physiological significance (Am 1). We will then examine the transcriptomes/methylomes of the two subsets to define the key methylated loci that can account for their distinct β-cell fitness, including testing if the differential Syt7 expression in the two β-cell subsets (observed by us) contributes to their different insulin secretion activities (Aim 2). Lastly, we will examine how maternal low-protein diet exposure impacts the derivation and fitness of M+N+ and M-N+ progenitor-derived β-cell subsets, focusing on the roles of enhanced Dnmt1 expression in mPPCs (Aim 3). We expect to impact the field by establishing direct mechanistic links between maternal factors and genetic networks that regulate functional β-cell mass and susceptibility to T2D. Our innovative combinatorial lineage marking of β-cell subsets put us in a unique position to study these issues.

功能不足的β细胞质量不足会导致2型糖尿病（T2D）。该应用将阐明胚胎多能胰腺祖细胞（MPPC）中的DNA甲基团如何预先确定。在胚胎发生过程中，MPPC激活前分泌转录因子（TF）NGN3产生内分泌祖细胞（EPC），从中得出β细胞。 DNA甲基化是一种相对稳定的反射标记，由包括DNA甲基转移酶1（DNMT1）在内的几种酶制定。 DNMT1多态性与衰减的β细胞功能和人类T2D有关。我们表明，胎儿暴露于孕产妇低蛋白饮食（已知会损害功能性β细胞质量），可增强小鼠MPPC中的DNMT1表达。我们最近发表了MPPC和EPC池都可以分为可能具有启发性基因增强子的子集，这些子集具有不同的DNA甲基化水平，这些基因增强子可能会偏向胰岛的命运选择。此外，MPPC/EPC中较高的DNMT1表达有利于β细胞分化。然而，EPC对胰岛细胞的分化涉及在调节β细胞增殖和功能的基因的假定增强子中，DNMT1的快速下调和一致的脱甲基化（称为适应性）。后者包括突触7（SYT7），这是一种促进葡萄糖刺激的胰岛素分泌的基因。我们的模型是，MPPC中的甲基组会影响其后代EPC和β细胞中进化的甲基组。通过预先设置基因的表达水平，这种基因的表达水平将在后来因高β细胞适应性质量而被激活，因此具有独特的甲基组的MPPC可以引起具有不同适应性的β细胞子集。通过改变DNMT1表达和/或母体饮食操纵的扰动早期甲基组将移动β细胞亚群的部分，因此功能性β细胞质量以及对T2D的敏感性。与该模型一致，我们表明，从正常生理学下，源自NGN3+ EPC的一部分（〜55％）衍生自NGN3+ EPC的子集（即MYT1+ NGN3+或“ M+ N+”）具有比M-N+细胞更高的NGN3+ EPC（即MYT1+ NGN3+或“ M+ N+”）更高。在这里，我们将首先定义M+ N+或M-N+祖细胞衍生的β细胞亚群的适应性，例如衰老，高血糖或胰岛素抵抗，以阐明其物理意义（AM 1）。然后，我们将检查两个亚群的转录组/甲基组，以定义可以说明其独特的β细胞适应性的关键甲基化基因座，包括测试是否在两个β细胞亚群中的差异SYT7表达（美国观察到）是否有助于其不同的胰岛素分泌活性（AIM 2）。最后，我们将研究产妇低蛋白饮食暴露如何影响M+ N+和M-N+祖细胞来源的β-Cell亚群的推导和适应性，重点是增强MPPC中DNMT1表达的作用（AIM 3）。我们期望通过在调节功能性β细胞质量和对T2D的易感性的遗传网络之间建立直接的机械联系来影响该领域。我们对β细胞亚群的创新组合谱系标记使我们处于研究这些问题的独特位置。

项目成果

期刊论文数量（5）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Microtubules regulate pancreatic β-cell heterogeneity via spatiotemporal control of insulin secretion hot spots.

DOI：
10.7554/elife.59912
发表时间：
2021-11-16
期刊：
eLife
影响因子：
7.7
作者：
Trogden KP;Lee J;Bracey KM;Ho KH;McKinney H;Zhu X;Arpag G;Folland TG;Osipovich AB;Magnuson MA;Zanic M;Gu G;Holmes WR;Kaverina I
通讯作者：
Kaverina I

Myt Transcription Factors Prevent Stress-Response Gene Overactivation to Enable Postnatal Pancreatic β Cell Proliferation, Function, and Survival.

DOI：
10.1016/j.devcel.2020.06.007
发表时间：
2020-06-22
期刊：
Developmental cell
影响因子：
11.8
作者：
Hu R;Walker E;Huang C;Xu Y;Weng C;Erickson GE;Coldren A;Yang X;Brissova M;Kaverina I;Balamurugan AN;Wright CVE;Li Y;Stein R;Gu G
通讯作者：
Gu G

Microtubules and Gαo-signaling modulate the preferential secretion of young insulin secretory granules in islet β cells via independent pathways.