Molecular Signalling Pathways and Cellular Stress in Diabetic Embryopathy

妊娠期糖尿病引起的神经管缺陷（NTDs）仍然是一个重要的健康问题。激酶信号诱导的细胞应激被认为是NTD形成的一个因果事件。然而，与神经发育相关的应激改变发育程序的原因仍然难以捉摸。我们发现母体的1型和2型糖尿病都会导致发育中的神经管过早衰老。我们还观察到，删除p21基因或p27基因，衰老介质，改善糖尿病诱导的NTD形成。此外，在培养细胞中诱导衰老的microRNA-200c/141 （miR-200c/141）位点的缺失通过下调转录抑制因子ZEB1和ZEB2来消除衰老介质的增加。糖尿病升高的miR-200c/141表达被超氧化物歧化酶1过表达消除。因此，我们假设母体糖尿病通过氧化应激激活的ASK1-FoxO3a通路上调miR-200c/141，诱导发育中的神经上皮增殖细胞过早衰老，导致神经褶融合失败。miR-200c/141通过抑制转录抑制因子ZEB1和ZEB2上调衰老介质p21和p27。这些衰老介质阻止增殖的顶端神经上皮细胞的细胞周期进程，导致NTDs。目的1将确定神经期过早衰老的特征，以及糖尿病诱导的氧化应激是否是糖尿病妊娠衰老的原因。我们假设糖尿病在发育中的神经上皮中特异性诱导p21的表达，从而抑制神经襞融合导致过早衰老，糖尿病诱导的氧化应激是增殖性顶端神经上皮细胞衰老的原因。Aim 2将研究氧化应激激活的ASK1-FoxO3a通路是否会增加miR-200c/miR-141，而miR-200c/miR-141介导母体糖尿病诱导的过早衰老和NTDs。我们将研究糖尿病通过ASK1-FoxO3a途径诱导miR-200c/141， miR-200c/141缺失通过释放ZEB1/2表达抑制p21表达，从而抑制过早衰老和NTDs。目的3将确定p21和p27是否会诱导糖尿病妊娠中顶端神经上皮细胞的细胞周期阻滞，从而导致过早衰老和NTD的形成。我们将验证p21和p27介导糖尿病胚胎病细胞周期阻滞和过早衰老的假设，以及p21和/或p27的缺失改善衰老和NTDs的假设。我们将继续探索关键激酶信号在衰老（一个新的发育程序）在糖尿病胚胎病中的作用，并揭示miRNAs如何参与母体糖尿病诱导的衰老。

Pregestational diabetes-induced neural tube defects (NTDs) remain a significant health problem. Kinase signaling-induced cellular stress is considered to be a causal event in NTD formation. However, the cause of stress-altered developmental programming relative to neurulation remains elusive. We found that both maternal type 1 and type 2 diabetes induce premature senescence in the developing neural tube. We also observed that deleting either the p21 gene or the p27 gene, the senescence mediators, ameliorates diabetes-induced NTD formation. Additionally, deletion of the microRNA-200c/141 (miR-200c/141) locus, which induces senescence in cultured cells, abolishes the increase of senescence mediators through the downregulation of the transcriptional repressor ZEB1 and ZEB2. Diabetes-increased miR-200c/141 expression is abrogated by superoxide dismutase 1 overexpression. Thus, we hypothesize that maternal diabetes induces premature senescence in proliferative cells of the developing neuroepithelium leading to failed neural fold fusion through up-regulation of miR-200c/141 by the oxidative stress-activated ASK1-FoxO3a pathway. miR-200c/141 up-regulates senescence mediators p21 and p27 through suppression of transcription repressors, ZEB1 and ZEB2. These senescence mediators arrest cell cycle progress of proliferative apical neuroepithelial cells leading to NTDs. Aim 1 will determine the characteristics of premature senescence during neurulation and whether diabetes-induced oxidative stress is the cause of senescence in diabetic pregnancy. We hypothesize that diabetes induces p21 expression specifically in the developing neuroepithelium leading to premature senescence in inhibiting neural fold fusion, and diabetes-induced oxidative stress is responsible for the induction of senescence in proliferative apical neuroepithelial cells. Aim 2 will investigate whether the oxidative stress-activated ASK1-FoxO3a pathway increases miR-200c/miR-141 that mediates maternal diabetes-induced premature senescence and NTDs. We will examine that diabetes induces miR-200c/141 through the ASK1-FoxO3a pathway, and that miR-200c/141 deletion suppresses p21 expression through liberating ZEB1/2 expression leading to inhibition of premature senescence and NTDs. Aim 3 will determine whether p21 and p27 induce cell cycle arrest in apical neuroepithelial cells leading to premature senescence and NTD formation in diabetic pregnancy. We will test the hypothesis that both p21 and p27 mediate cell cycle arrest and premature senescence in diabetic embryopathy, and that deletion of p21 and/or p27 ameliorates senescence and NTDs. We will continue to explore the role of key kinase signaling in senescence, a new developmental program, in diabetic embryopathy and to reveal how miRNAs participates in maternal diabetes-induced senescence.