Molecular Mechanisms in Diabetic Embryopathy

糖尿病胚胎病的分子机制

基本信息

批准号：
8066263
负责人：
Claudia T Kappen
金额：
$ 23.44万
依托单位：
LSU PENNINGTON BIOMEDICAL RESEARCH CTR
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-08-01 至 2012-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8066263
关键词：
Adult Affect Biological Assay Birth Cell Death Cell Differentiation process Cell Proliferation Cells Congenital Abnormality Congenital Heart Defects Databases Defect Dependency Development Diabetes Mellitus Diabetic mother Diabetic mouse Dose Elements Embryo Embryonic Development Enhancers Environment Etiology Fetal Development Gene Dosage Gene Expression Gene Expression Profiling Gene Targeting General Population Genes Genetic Genetic Models Goals Growth Heart Human Individual Infant Inherited Islet Cell Link Mediating Mesoderm Messenger RNA Metabolic Metabolic Diseases Modeling Molecular Molecular Profiling Morbidity - disease rate Mothers Mus Mutation Neural Tube Defects Neural tube Pancreas Pathogenesis Pathway interactions Pattern Pharmaceutical Preparations Phenotype Pregnancy Pregnancy in Diabetics Prevention strategy Progress Reports Regulation Regulatory Element Reporter Reproducibility Research Personnel Risk Role Sacral agenesis Sampling Screening procedure Series Signal Pathway Somatostatin Surveys Syndrome System Tail Time Transcription factor genes Transcriptional Regulation Transgenes Transgenic Mice Transgenic Organisms Work base cDNA Arrays diabetic diabetic embryopathy dosage insight islet mortality mouse model mutant novel pancreas development programs research study transcription factor

项目摘要

The risk for birth defects is 3 to 10-fold higher in diabetic pregnancy, and congenital malformations are the main cause of mortality and morbidity in infants born to mothers with diabetes. To devise preventive strategies for diabetic embryopathy, it is necessary to understand its etiology and pathogenesis at the molecular level. Our hypothesis is that metabolic imbalance in diabetic pregnancy de-regulates the expression of pancreatic transcription factors in the developing embryo, thus causing diabetic embryopathy. This idea is supported by transgenic paradigms. In mice, transgenes for the pancreatic transcription factor Isl-1 induce phenotypes that resemble human diabetic embryopathy, specifically neural tube and caudal growth defects. In humans, mutant HLXB9, a pancreatic transcription factor downstream of Isl-1, causes sacral agenesis. We have shown that the basis for caudal growth deficiency is a gone dosage-correlated insult to the mesoderm. Our model states that de-regulation of Isl-1 leads to de-regulation of its downstream target genes that, in turn, are the effectors for pathogenesis of the birth defect phenotype. Two key questions arise from our hypothesis: (i) Which factors regulate Isl-1 in the embryo, and how can Isl-1 expression become deregulated in diabetic pregnancy? (ii) Which downstream pathways are altered, and are they also involved in other posterior growth defects? Experimentally, we pursue the following specific aims: (1) To identify the regulatory elements for normal Isl-1 expression in the embryo, and determine how diabetes affects their activity. We have already identified a caudal region-specific enhancer in the Isl-1 locus, which is a candidate control element for de-regulation by metabolic imbalance. The functional role of gene regulatory elements in diabetic embryopathy will be established in murine pregnancies with genetic or experimentally induced diabetes. (2) To identify targets of Isl-1, and to investigate their role in the pathogenesis of caudal growth defects. To recognize Isl-1 targets in our Isl-1 transgenic mouse system, we will use microarray-based gene expression profiling. Preliminary quantitative real-time PCR results implicate the somatostatin and Wnt signaling pathways in Isl-l-induced caudal growth defects. Novel targets, together with the previously identified targets Pbx-1, Punc, and Hlxb9, will be evaluated in genetic models of caudal deficiencies, and progeny of diabetic pregnancies. These experiments will generate new and comprehensive insights into the function of pancreatic transcription factors and their pathogenic potential in metabolic disease and fetal development.

糖尿病妊娠的先天缺陷的风险为3至10倍，先天性畸形是糖尿病母亲出生的婴儿死亡率和发病率的主要原因。为了制定糖尿病性胚胎病的预防策略，有必要在分子水平上了解其病因和发病机理。我们的假设是，糖尿病妊娠中的代谢失衡会取消调节胰腺转录因子在发育中的胚胎中的表达，从而导致糖尿病性胚胎病。这个想法得到了转基因范式的支持。在小鼠中，胰腺转录因子ISL-1的转基因诱导类似于人类糖尿病胚胎的表型，特别是神经管和尾部生长缺陷。在人类中，ISL-1下游的胰腺转录因子突变HLXB9会导致骨发育不全。我们已经表明，尾状生长缺乏的基础是与中胚层相关的剂量侮辱。我们的模型指出，ISL-1的消除导致其下游靶基因的下调，这反过来又是出生缺陷表型发病机理的效应子。我们的假设提出了两个关键问题：（i）哪些因素调节胚胎中的ISL-1，以及在糖尿病妊娠中ISL-1表达如何在失调中？（ii）哪些下游途径发生了变化，并且它们还参与其他后部生长缺陷吗？在实验上，我们追求以下特定目的：（1）确定胚胎中正常ISL-1表达的调节元素，并确定糖尿病如何影响其活性。我们已经确定了ISL-1基因座中的尾区特异性增强子，这是通过代谢失衡来消除调节的候选控制元件。基因调节元件在糖尿病胚胎病中的功能作用将在遗传或实验诱导的糖尿病的鼠妊娠中确定。（2）确定ISL-1的靶标，并研究其在尾部生长缺陷的发病机理中的作用。为了识别我们的ISL-1转基因小鼠系统中的ISL-1靶标，我们将使用基于微阵列的基因表达分析。初步定量的实时PCR结果暗示了ISL-L诱导的尾部生长缺陷中的生长抑素和Wnt信号通路。新的目标以及先前确定的靶标PBX-1，PANC和HLXB9将在尾缺乏症的遗传模型和糖尿病妊娠后代进行评估。这些实验将对胰腺转录因子的功能及其在代谢疾病和胎儿发育中的致病潜力产生新的全面见解。