Molecular Signalling Pathways and Cellular Stress in Diabetic Embryopathy

妊娠期糖尿病引起的神经管缺陷(NTDS)仍然是一个重大的健康问题。激酶信号诱导的细胞应激被认为是NTD形成的原因事件。然而，与神经形成相关的应激改变发育编程的原因仍然难以捉摸。我们发现，母体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，删除衰老调节因子p21基因或p27基因，可以改善糖尿病引起的神经功能障碍的形成。此外，导致培养细胞衰老的microRNA-200C/141(miR-200C/141)基因座的缺失，通过下调转录抑制因子ZEB1和ZEB2，取消了衰老介质的增加。糖尿病增加的miR-200C/141的表达被超氧化物歧化酶1的过度表达所取消。因此，我们假设，母亲糖尿病通过氧化应激激活的ASK1-FOXO3a途径上调miR-200C/141，导致发育中的神经上皮细胞增殖细胞提前衰老，导致神经折叠融合失败。MIR-200C/141通过抑制转录抑制因子ZEB1和ZEB2上调衰老调节因子p21和p27。这些衰老介质阻止了增殖的顶端神经上皮细胞的细胞周期进程，导致NTDS。目的1将确定神经形成过程中早衰的特征，以及糖尿病引起的氧化应激是否是糖尿病妊娠衰老的原因。我们假设糖尿病诱导p21在发育中的神经上皮细胞中特异地表达，从而抑制神经折叠融合而导致过早衰老，而糖尿病诱导的氧化应激是诱导增殖的心尖神经上皮细胞衰老的原因。目的2将研究氧化应激激活的ASK1-FOXO3a通路是否增加了miR-200C/miR-141，从而介导了母亲糖尿病诱导的早衰和NTDS。我们将研究糖尿病通过ASK1-FOXO3a途径诱导miR-200C/141，而miR-200C/141缺失通过释放ZEB1/2表达抑制p21的表达，从而抑制早衰和NTDS。目的3研究p21和p27在糖尿病妊娠中是否诱导顶端神经上皮细胞细胞周期停滞，导致早衰和神经管畸形形成。我们将检验p21和p27在糖尿病胚胎病变中都介导细胞周期停滞和早衰的假设，以及p21和/或p27的缺失可以改善衰老和NTDS。我们将继续探索关键激酶信号在衰老中的作用，这是一个新的发育计划，在糖尿病胚胎病变中发挥作用，并揭示miRNAs如何参与母亲糖尿病诱导的衰老。

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.