Preoptic/Hypothalamic Mechanisms of Sleep-Wake Regulation

摘要 慢性睡眠障碍是人类老龄化过程中常见且具有挑战性的问题。在美国， 估计有3960万人，包括850万退伍军人，年龄在65岁或以上，有发展的风险。 慢性睡眠障碍慢性睡眠不足或睡眠中断与多种不良健康状况有关 结果，包括跌倒风险增加，认知能力下降，焦虑，抑郁症和阿尔茨海默氏症 疾病此外，老年退伍军人的医疗和精神疾病的患病率很高， 加重睡眠障碍。 最近，我们发现，慢性抑制下丘脑细胞增殖的年轻小鼠， 产生了衰老的睡眠-觉醒特征，包括睡眠中断和对睡眠不足的反应不良。在这里， 我们提出了一系列新的临床前研究，将使用互补和尖端的方法， 检查：a）下丘脑神经发生是否通过维持新细胞的供应来调节睡眠功能， 替代衰老的睡眠调节腹外侧视前区甘丙肽（VLPOGAL）和GABA（VLPOGABA） 神经元; B）如果是下丘脑神经发生的破坏，由伴随的慢性炎症引起 衰老，导致生理功能障碍和/或关键的睡眠调节VLPOGAL的丧失， VLPOGABA神经元和随之而来的衰老中的睡眠障碍;以及c）如果衰老中的睡眠障碍可能是 通过神经再生和抗炎方法减轻。 具体目标-1：将确定下丘脑神经发生是否对维持下丘脑的功能至关重要。 VLPO睡眠调节神经元群，其损伤是其功能下降的驱动因素， 睡眠中断在老化。我们将确定细胞增殖、迁移和分化的程度， 前体细胞转化为睡眠调节VLPOGAL和VLPOGABA神经元及其睡眠相关激活 在年轻和老年小鼠中，以及在慢性抑制神经发生后的年轻小鼠中（实验-1）。我们 预测老年小鼠或下丘脑神经发生受损的小鼠将表现出：a）细胞数量下降， 前体细胞增殖并分化成VLPOGAL和VLPOGABA神经元，B）较少的VLPOGAL 和VLPOGABA神经元表现出渗出相关的Fos免疫反应性;和c）更多的睡眠中断。我们 将使用钙成像来确定VLPOGAL神经元是否表现出与缺陷平行的功能衰退， 在老化的自发和受损的稳态睡眠反应中（实验2）。我们将使用 化学发生激活，以确定VLPOGAL神经元在干扰后促进睡眠的能力。 神经发生，一种低度炎症，以及在神经发生性炎症存在下破坏神经发生后， 确定VLPOGAL神经元在慢性抑制后促进睡眠的能力是否下降的因素 睫状神经营养因子（CNTF）可减弱下丘脑神经发生的作用。 具体目标-2：将确定是否增加VLPO睡眠的下丘脑细胞增殖和神经发生 调节神经元改善老年小鼠的睡眠结构和睡眠连续性。我们将决定是否在 老年小鼠，持续诱导下丘脑细胞增殖的ICV输注CNTF，一种神经源性 一种对神经炎性病变具有保护作用的因子，增加迁移和分化 神经突起转化为成熟的VLPOGAL神经元;减少神经炎症和衰老;并减少 睡眠片段化（实验-4）。我们将使用化学发生激活来确定 在老年小鼠中，在CNTF治疗后，促进睡眠的VLPOGAL神经元得到改善（实验-5）。 从这些临床前研究中获得的数据将提供对机制的见解 睡眠中断的潜在原因我们的研究还包括药理学元素， 优化老年人睡眠健康的治疗选择，包括老年退伍军人

ABSTRACT Chronic sleep disturbance is a frequent and challenging problem of human aging. In the US an estimated 39.6 million people including 8.5 million Veterans are aged 65 or older and at risk of developing chronic sleep disturbance. Chronic insufficient or disrupted sleep is associated with multiple adverse health outcomes, including increased risk of fall, cognitive decline, anxiety, depressive disorders, and Alzheimer's disease. Also, elderly Veterans have a high prevalence of medical and psychiatric disorders that can further aggravate sleep disturbance. Recently, we found that chronic suppression of hypothalamic cell proliferation in young mice produced sleep-wake features of aging including sleep disruption and poor response to sleep loss. Here, we proposes a series of novel preclinical studies that will use complimentary and cutting edge approaches to examine: a) if hypothalamic neurogenesis regulates sleep function by maintaining a supply of new cells to replace senescent sleep-regulatory ventrolateral preoptic area galanin (VLPOGAL) and GABA (VLPOGABA) neurons; b) if a disruption of hypothalamic neurogenesis, caused by chronic inflammation that accompanies aging, contributes to physiological dysfunction and or loss of the critical sleep-regulatory VLPOGAL and VLPOGABA neurons and consequent sleep disturbance in aging; and c) if sleep disturbance in aging could be mitigated by neuro-regenerative and anti-inflammatory approaches. Specific aim-1: will determine if hypothalamic neurogenesis is vital for maintaining the functioning of the VLPO sleep regulatory neuronal groups and that its impairment is a driver of their functional decline and sleep disruption in aging. We will determine the extent of cell proliferation, migration, and differentiation of precursor cells into sleep regulatory VLPOGAL and VLPOGABA neurons and their sleep-associated activation in young and old mice, and in young mice after chronic suppression of neurogenesis (experiment-1). We predict that old mice or mice with impaired hypothalamic neurogenesis will exhibit: a) a decline in cell proliferation and differentiation of precursor cells into VLPOGAL and VLPOGABA neurons, b) fewer VLPOGAL and VLPOGABA neurons exhibiting seep-associated Fos-immunoreactivity; and c) more sleep disruption. We will use calcium imaging to determine if VLPOGAL neurons exhibit a functional decline, paralleling the deficits in spontaneous and impaired homeostatic sleep responses in aging (experiment-2). We will use chemogenetic activation to determine the ability of VLPOGAL neurons to promote sleep after disrupting neurogenesis, a low grade inflammation, and after disrupting neurogenesis in the presence of a neurogenic factor to determine if a decline in the ability of VLPOGAL neurons to promote sleep after chronic suppression of hypothalamic neurogenesis is attenuated by ciliary neurotrophic factor (CNTF). Specific aim-2: will determine if increasing hypothalamic cell proliferation and neurogenesis of VLPO sleep regulatory neurons improves sleep architecture and sleep continuity in old mice. We will determine if in aged mice, sustained induction of hypothalamic cell proliferation by ICV infusion of CNTF, a neurogenic factor with a protective role against neuroinflammatory pathologies, increases migration and differentiation of neurites into mature VLPOGAL neurons; decreases neuroinflammation and senescence; and reduces sleep fragmentation (experiment-4). We will use chemogenetic activation to determine if the ability of VLPOGAL neurons to promote sleep improves after CNTF treatment in old mice (experiment-5). The data obtained from these preclinical studies would provide insights into the mechanisms underlying sleep disruption in aging. Our studies also include pharmacological elements that could provide therapeutic options for optimizing sleep health in the elderly including elderly Veterans