This supplement application aims to test how maternal low-protein diet exposure during fetal development impacts the function and viability of neurons in postnatal mouse hypothalamus and hippocampus. The hypothesis is that intrauterine factors modulate the DNA methylomes of embryonic neuronal progenitor cells; this methylation pattern predetermines the expression levels of key neuronal genes and therefore preset the risk of Alzheimer’s diseases and related diseases (ADRD) in adult ages. Specifically, we will focus on the neurons that are derived from embryonic progenitor cells that express transcription factor Neurogenin 3 (a.k.a. Neurog3 or Ngn3). Published studies have shown that these Ngn3+ progenitors give rise to neurons in the hypothalamus and hippocampus, whose deteriorating function is closely associated with ADRD. Thus, we will purify embryonic Ngn3+ neural progenitor cells as well as their adult descendants in mouse brains and examine the methylome and transcriptome of these cells. These patterns will be directly compared between control mice and those exposed to maternal low-protein diet. In addition, immunoassays in some key candidate genes will be conducted, including Syt1, Syt7, APP, and Tau, important for neuronal function and associated with ADRD, respectively. Our preliminary data showing the regulation of these two candidates by DNA methylation justify these assays. Basic behavioral assays will also used to correlate the physiological phenotype with the DNA methylation states. Notably, these studies are parallel to what will be pursued in the Aim 3 of the parent R01, which examines how intrauterine factors impact the methylomes/transcriptomes of Ngn3+ islet beta-cell progenitors and the function of their adult progeny in the context of type 2 diabetes (T2D). These supplement studies therefore rely on identical mouse models, same techniques, and similar expertise as those proposed in the parent R01. More importantly, it has long been recognized that T2D and ADRD are tightly linked with each other; the risks of both diseases are heavily affected by the intrauterine history. Thus, examining the overlapping and distinct mechanisms in the development/function of Ngn3+ lineages, one in the pancreas the other in the brain, is expected to yield potential targets to interfere with the development both diseases.