Deconstructing insulin in the brain in relation to Alzheimer's Disease

初步结果： 1. 我们发现胰岛素在人和小鼠脉络丛中在mRNA和蛋白质水平上都有显著表达。小鼠脉络丛（CP）中的胰岛素异构体mRNA水平约为胰腺的10%，这是一个意想不到的发现。 CP胰岛素含量是所有组织中第二高的-仅次于通常的胰腺来源的胰岛素-和我们通过RT-qPCR和原位杂交（ISH）技术调查的脑区域。 2. 我们已经开发了一种蛋白质组学面板，以分别和准确地定量人受试者CSF和血浆中胰岛素的α和β亚基以及衍生自胰岛素原的C肽。 3. 我们已经在人和小鼠基因组中发现了新的胰岛素启动子，并且新的启动子在脑CP中比在胰腺中更活跃。 4. 与HBCC-NIMH合作，我们已经确定了胰岛素在1型糖尿病死后CP中表达。 5. 我们已经发现，在淀粉样蛋白沉积的症状前阶段（2个月大），2XTG AD小鼠模型中CP胰岛素水平发生改变。 未来： 我们将与部门的Juan Troncoso博士合作，研究CP衍生胰岛素与AD病理学的任何相关性。JHMS将收集AD死亡前不同阶段的尸检CP和对照样本。 我们将研究人AD与对照样品中的CSF胰岛素水平。小鼠有两个胰岛素基因：Ins 1和Ins 2。我们在种系Ins 1敲除小鼠的背景下创建了Ins 2-flox小鼠。该小鼠系将与Foxj 1-Cre-ERT-GFP小鼠杂交以产生CP特异性他莫昔芬诱导的条件性敲除小鼠，以研究CP胰岛素的功能及其在与AD发展相关的脑胰岛素抵抗中的作用。我们将探索生物制剂对抗胰岛素接种的潜力，胰岛素接种是β-淀粉样蛋白寡聚化和斑块形成的原因。而且，在一个非常基本的水平上，我们需要揭示是什么控制着CP中胰岛素的合成和分泌。

Preliminary results: 1. We have found that insulin is significantly expressed at both mRNA and protein levels in human and mouse choroid plexus. The mouse insulin isoform mRNA levels in choroid plexus (CP) are about 10% of those of pancreas an unexpected finding. CP insulin content is the second highest among all tissues - second only to the usual pancreatic-derived insulin - and brain regions that we surveyed by RT-qPCR and in situ hybridization (ISH) techniques. 2. We have developed a proteomic panel to quantify separately and accurately alpha and beta subunits of insulin, as well as C- peptides derived from proinsulin, in CSF and plasma of human subjects. 3. We have discovered novel insulin promoters in human and mouse genome and the novel promoters are more active in brain CP than in pancreas. 4. In collaboration with HBCC-NIMH, we have identified that insulin is expressed in type 1 diabetes postmortem CP. 5. We have found that CP insulin levels are altered in 2XTG AD mouse model at presymptomatic stage (2 months of age) of amyloid deposition. Future: We will investigate for any CP-derived insulin association with AD pathology in collaboration with Dr. Juan Troncoso at Dept. of Pathology, JHMS who will collect post-mortem CP in different stages of AD prior to death and control samples. We will investigate CSF insulin levels in human AD vs controls samples. Mice have two insulin genes: Ins1 and Ins2. We have created Ins2-flox mice on the background of germline Ins1 knockout mice. This mouse line will be crossed with Foxj1-Cre-ERT-GFP mice to generate CP specific tamoxifen-inducible conditional knockout mice to study the function of CP insulin and its role in brain insulin resistance related to AD development. We will explore the potential of biologics to counteract insulin seeding as a cause of beta-amyloid oligomerization and plague formation. And, at a very basic level, we need to uncover what governs insulin synthesis and secretion in CP.