Prevention of Placental Insufficiency Improves Beta-Cells Function

摘要 胰岛功能障碍是2型糖尿病发病机制中的一个标志性特征， 胎盘功能不全（PI）和胎儿生长受限（FGR）的发育适应。我们已经确定 胰岛素产生和分泌的显著减少在FGR后代中持续存在。我们努力阐明 FGR胰岛中的编程机制表明，正常的组成型核因子κ B (NFκB）活性对胰岛素分泌有负面影响。此外，我们的初步发现与抑郁症 NFκB活性与低氧诱导的MALAT 1表达有关，因为这种长的基因间非编码（linc）RNA 结合NFκB以防止活化。本项目的指导前提是低胎氧和低血糖 在发育期间，来自PI的高浓度引起β细胞功能障碍。因此，我们计划纠正氧气， 在PI期间FGR胎儿的葡萄糖浓度，并显示胰岛素分泌和β细胞 增殖基础实验表明，联合补充氧气和葡萄糖， PI诱导FGR的胎儿改善胰岛素分泌，但导致持续性β细胞 失败未被发现。我们假设PI-FGR中氧和葡萄糖浓度的校正 胎儿正常，控制胎儿值将通过增强β细胞增殖和胰岛素抵抗来防止β细胞功能障碍 通过恢复组成性和生理性NFκB活性来分泌。此外，胎儿氧气和 葡萄糖校正将解决FGR羔羊的β细胞中的程序性缺陷。我们已经调整了胎儿 PI-FGR绵羊模型，以测试在受控的子宫内的氧气和葡萄糖的补充混合物， 环境初步实验中，五天的氧气和葡萄糖校正降低了去甲肾上腺素， 增加胰岛素，并恢复胰岛中葡萄糖刺激的胰岛素分泌（GSIS），证明其适用性 作为测试逆转PI的能力是否改善β细胞衰竭的模型。在目标1中，我们将评估 氧和葡萄糖校正对改善PI胎儿和新生儿β细胞功能的联合作用- 诱发FGR。在目标2中，我们将确定GSIS中的局限性，这些局限性是由较低的组成型NFκB活性引起的， FGR胰岛中MALAT 1过表达。通过缓解低氧血症和提供葡萄糖， β细胞的反应性，我们预计胰岛素分泌和β细胞增殖将增加和编程 导致β细胞功能障碍的机制将恢复正常。这些实验的影响将很大，因为它们 将提供有关PI诱导胎儿β细胞功能障碍可逆性的基础新知识 FGR。此外，我们的实验将确定NFκB调控FGR胎儿β细胞的独特作用 导致持续降低胰岛素分泌的发育适应。我们还将获得新的见解， 当胎儿氧和葡萄糖被纠正时，一种独特的胰岛编程机制的可逆性， 预计将改善FGR患者的短期和长期结局。

Abstract Pancreatic islet dysfunction is a signature feature in the pathogenesis of Type 2 Diabetes and can stem from developmental adaptations to placental insufficiency (PI) and fetal growth restriction (FGR). We have identified significant reductions in insulin production and secretion that persist in offspring with FGR. Our efforts to elucidate programming mechanisms in FGR islets indicate that reductions in normal, constitutive nuclear factor kappa B (NFκB) activity negatively affects insulin secretion. Additionally, our preliminary findings associate depressed NFκB activity with hypoxia-induced MALAT1 expression because this long intergenic non-coding (linc) RNA binds NFκB to prevent activation. The guiding premise of this project is that low fetal oxygen and glucose concentrations from PI cause β-cell dysfunction during development. Therefore, we plan to correct oxygen and glucose concentrations in FGR fetuses during PI and show improvements in insulin secretion and β-cell proliferation. Foundational experiments demonstrate that combined supplementation of oxygen and glucose to the fetus with PI-induced FGR improves insulin secretion, but the underlying cues that cause persistent β-cell failure are undiscovered. We hypothesize that correction of oxygen and glucose concentrations in the PI-FGR fetus to normal, control fetal values will prevent β-cell dysfunction by enhancing β-cell proliferation and insulin secretion through the restoration of constitutive and physiological NFκB activity. Furthermore, fetal oxygen and glucose correction will resolve programmed deficiencies in β-cells of FGR lambs. We have adapted our fetal sheep model of PI-FGR to test a supplemental mixture of oxygen and glucose in a controlled, in utero environment. Preliminary experiments with five days of oxygen and glucose correction lowered norepinephrine, increased insulin, and restored glucose-stimulated insulin secretion (GSIS) in islets, demonstrating its suitability as a model to test whether the capacity to reverse PI ameliorates β-cell failure. In Aim 1, we will evaluate the combined effect of oxygen and glucose correction to improve β-cell function in fetuses and neonates with PI- induced FGR. In Aim 2, we will determine limitations in GSIS that result from lower constitutive NFκB activity due to MALAT1 overexpression in FGR islets. By alleviating hypoxemia and providing glucose, a major nutrient for β-cell responsiveness, we expect that insulin secretion and β-cell proliferation will increase and programming mechanisms causing β-cell dysfunction will return to normal. Impact of these experiments will be high, as they will provide fundamental new knowledge about the reversibility of β-cell dysfunction in fetuses with PI-induced FGR. In addition, our experiments will define the unique roles for NFκB regulation in β-cells from FGR fetuses that cause developmental adaptations that persistently lower insulin secretion. We also will gain new insight on the reversibility of a distinct islet-programming mechanism when fetal oxygen and glucose is corrected, which is expected to improved short- and long-term outcomes in individuals with FGR.