ESTROGEN-INDUCIBLE PNNS ENHANCE EXCITATORY SYNAPTIC STRENGTH ONTO GABA NEURONS IN THE MEPD TO PREVENT OBESITY AND METABOLIC DYSREGULATION

项目摘要 神经元周围网是一组神经元周围的细胞外基质。PNN可以提供 对神经元的物理保护和离子缓冲，并调节其突触可塑性和细胞内信号传导。 最近的证据表明，PNNs在下丘脑弓状核（ARH）中与GABA神经元缠结 来调节能量和葡萄糖的体内平衡然而，关于其潜在的代谢功能知之甚少。 PNN在其他大脑区域也与代谢健康有关。 我们在背内侧杏仁核（MePD）中观察到丰富的PNN， MePD中的神经元主要是GABA神经元。PNN的消化大大降低了兴奋性和突触 这些GABAMePD神经元的活动。重要的是，我们发现MePD PNN的慢性破坏导致 摄食过多和适度的体重/脂肪增加。另一方面，MePD PNN的慢性增加 导致在普通饲料喂养的小鼠中体重/脂肪降低。这些结果表明MePD PNN和PNN-缠结 GABAMePD神经元是防止暴饮暴食和肥胖所必需的。我们会跟进调查结果， MePD PNNs（Aim 1）和GABAMePD（Aim 2）神经元在能量和葡萄糖稳态中的功能。 同时，我们将阐明PNN调节兴奋性和突触活动的机制， GABA MePD神经元。 17β-雌二醇（E2）可作用于雌激素受体-α（ERα），调节两种细胞的能量和葡萄糖平衡。 女性和男性。以前的研究表明，ERα在许多脑区介导的代谢作用， E2仅在雌性小鼠中，而不是雄性小鼠。我们的初步观察表明，E2可以增加MePD中的PNN 在雄性和雌性小鼠中。重要的是，内侧杏仁核（含有MePD）中ERα的缺失导致 肥胖不仅在雌性小鼠中，而且在雄性小鼠中，这表明MePD在雄性小鼠中的潜在代谢作用。 代谢健康在目标3中，我们将跟踪这些发现，以测试E2是否诱导PNNs促进GABA MePD中的神经元，以防止雄性和雌性小鼠的肥胖和代谢失调。 我们将揭示一种新的代谢调节机制：E2-ERα-PNNs-GABAMePD-能量/葡萄糖 体内平衡我们的研究将促进我们对女性和男性雌激素生物学的理解 代谢和PNNs在新脑区MePD中的代谢作用。最后，我们将确定一个独特的 产食欲的GABA神经细胞群，这与以前报道的产食欲的GABA神经细胞群不同， 许多其他脑区。

PROJECT SUMMARY Perineuronal nets (PNNs) are condensed extracellular matrix around a subset of neurons. PNNs can provide physical protection and ion buffering for neurons and regulate their synaptic plasticity and intracellular signaling. Recent evidence indicates that PNNs enmesh GABA neurons in the arcuate nucleus of the hypothalamus (ARH) to regulate energy and glucose homeostasis. However, little is known about the potential metabolic function of PNNs in other brain regions that are also implicated in metabolic health. We observed abundant PNNs in the posterodorsal medial amygdala (MePD) and found that PNN-enmeshed neurons in the MePD are mostly GABA neurons. Digestion of PNNs drastically reduces excitability and synaptic activity of these GABAMePD neurons. Importantly, we showed that chronic disruption of MePD PNNs leads to hyperphagia and modest weight/fat gain in chow-fed mice. On the other hand, chronic increases in MePD PNNs result in lower body weight/fat in chow-fed mice. These results suggest that MePD PNNs and PNNs-enmeshed GABAMePD neurons are required to prevent overeating and obesity. We will follow up these findings to establish the function of MePD PNNs (Aim 1) and GABAMePD (Aim 2) neurons in energy and glucose homeostasis. Meanwhile, we will delineate the mechanisms by which PNNs regulate excitability and synaptic activity of GABAMePD neurons. 17β-estradiol (E2) can act on estrogen receptor-α (ERα) to regulate energy and glucose balance in both females and males. Previous reports showed that ERα in many brain regions mediates the metabolic effects of E2 only in female mice, but not male mice. Our pilot observations indicate that E2 can increase PNNs in MePD in both male and female mice. Importantly, loss of ERα in the medial amygdala (containing the MePD) causes obesity not only in female mice, but also in male mice, suggesting the potential metabolic role of MePD in male metabolic health. In Aim 3, we will follow up these findings to test whether E2 induces PNNs to facilitate GABA neurons in the MePD to prevent obesity and metabolic dysregulation in both male and female mice. Together, we will reveal a new metabolic regulation mechanism: E2-ERα-PNNs-GABAMePD-energy/glucose homeostasis. Our studies will advance our understanding about the estrogen biology in both female and male metabolism and the metabolic role of PNNs in a new brain region MePD. Finally, we will identify a unique anorexigenic GABA population, which is different from previous reported orexigenic GABA neural populations in many other brain regions.