Investigating the role of mast cells in neonatal germinal matrix hemorrhage

在拟议的项目中，我们将研究肥大细胞在导致脑损伤的炎症和 导致新生儿出血性中风后的精神和神经障碍，特别是生发障碍 基质出血(GMH)。最重要的是，我们将测试GMH后肥大细胞的稳定是否会 减轻GMH引起的脑损伤，改善精神和神经功能。GMH是一种毁灭性的 每年影响12000多名早产儿的疾病，导致脑积水和脑瘫， 导致智力低下和终生残疾。近一半的低出生体重儿会发生GMH， 显著增加患抑郁症和强迫症的风险。此外，GMH诱导的 脑实质损害和脑室增大会增加注意力缺陷和多动的风险 无序。无残疾存活的GMH患者发生注意力障碍的风险明显更高。 缺乏症、焦虑症和情绪障碍。GMH引起的脑室扩大是一种强烈而显著的 自闭症谱系障碍和精神分裂症的危险因素。我们最近开发了一种 新生大鼠GMH模型及其所观察到的神经后遗症与 临床上可见于人类早产儿。在GMH幼崽中，我们观察到显著的发育延迟， 这会导致工作记忆的丧失(通过T-迷宫测试进行评估)，空间学习障碍(水 迷宫试验)、多动症(开场试验)以及青少年时期的运动功能障碍 发展阶段。在该模型中，我们证实了转化生长因子β1的积聚和转化生长因子β的激活。 通路在GMH后脑损伤中起重要作用。然而，该模型中活性转化生长因子β-1的来源 目前仍不清楚。在拟议项目的目标1中，我们将确定肥大细胞是否是GMH的主要参与者- 诱导转化生长因子β通路激活。最重要的是，我们将确定肥大细胞的稳定性是否会下降 GMH致脑损伤，改善智力功能。除了上面提到的测试，记录 对重复的刻板印象运动的观察将提供自闭症样和/或强迫症的测量 强迫行为。情感行为，包括焦虑和冒险行为，将用 零迷宫和抑郁/习得性无助的行为将使用强迫游泳来测量， 还有蔗糖偏好测试。最后，社交优势、方法和气味标记将通过以下指标来衡量 记录与接触新的雌性和雄性相关的观察。为了使肥大细胞稳定，我们将 使用1)奥马珠单抗，临床批准用于治疗病理性肥大细胞相关疾病的药物 2)吸入氢气，这是一种安全的治疗方法，没有报道过副作用。在目标2中，我们 将研究肥大细胞稳定化诱导脑保护的机制。我们假设，抑制 肥大细胞介质可抑制转化生长因子β的激活，从而通过下调IL-2的表达来减轻脑部炎症 17，导致GMH后脑损伤和神经功能障碍的减轻。

In the proposed project, we will study the role of mast cells in inflammation leading to brain injury and consequently to mental and neurological disorders after neonatal hemorrhagic stroke, specifically germinal matrix hemorrhage (GMH). Most importantly, we will test whether stabilization of mast cells after GMH will attenuate GMH-induced brain injury and improve mental and neurological functions. GMH is a devastating disease affecting over 12,000 premature infants annually, resulting in hydrocephalus and cerebral palsy, leading to mental retardation and lifelong disabilities. GMH, occurs in nearly half of low birth weight infants, significantly increases risk of depressive and obsessive-compulsive disorders. Additionally, GMH-induced parenchymal lesions and ventricular enlargement increases the risk of attention deficit and hyperactivity disorder. GMH patients who survive without disability will have significantly higher risk of developing attention deficit, anxiety, and mood disorder. GMH induced cerebral ventricular enlargement is a strong and significant risk factor for the development of autism spectrum disorders and schizophrenia. We recently developed a GMH model in neonatal rats and the neurological sequelae observed in this animal model were similar to that seen in human preterm neonates clinically. In the GMH pups, we observed a significant delay in development, which resulted in the loss of `working' memory' (evaluated by T-Maze test), impaired spatial learning (Water Maze test), and hyperactivity (Open Field test) as well as in motor dysfunctions during the juvenile development stage. In this model, we demonstrated that TGFβ1 accumulation and the activation of the TGFβ pathway significantly contributed to brain injury after GMH. However the source of active TGFβ1 in this model remains unclear. In Aim 1 of the proposed project, we will determine if mast cells are a major player in GMH- induced TGFβ pathway activation. Most importantly we will determine if mast cell stabilization will decrease GMH-induced brain injury and improve mental functions. In additional to tests mentioned above, recording observations of repetitive stereotypic movements will provide measures of autism-like and/or obsessive compulsive behaviors. Affective behaviors, including anxiety and risk-taking behaviors, will be assessed with the zero maze, and depression/learned-helplessness-like behaviors will be measured using the forced swim, and sucrose preference tests. Finally, social dominance, approach, and scent marking will be measured by recording observations associated with exposure to novel females and males. For mast cell stabilization we will use 1) Omalizumab, the drug clinically approved for treating the diseases related to pathologic mast cell activation in humans and 2) Hydrogen inhalation, a safe treatment without reported side effects. In Aim 2, we will study the mechanism of mast cell stabilization-induced brain protection. We hypothesize that inhibition of mast cell mediators will attenuate TGFβ activation thus decrease brain inflammation via downregulation of IL- 17, resulting in the attenuation of brain injury and neurological deficits after GMH.