The hippocampus neurogenic niche (HNN) generates new neurons in mammals, but it is unclear if this is
happening in humans. Adult hippocampal neurogenesis is necessary to maintain intact cognitive and emotional
functions regulated by the hippocampus. Markers of immaturity have been detected in neuronal cells of the HNN
but it is still unclear if they represent adult-born neurons, or neuronal cells that have maintained their immaturity
since birth. We found that the number of neural progenitor cells (NPCs) and immature neurons was stable
throughout the eighth decade of life in normal aging (NA) subjects, but angiogenesis and neuroplasticity were
decreased in older people. Other groups have supported our findings, while some could not detect immature
neuronal cells in human hippocampus. Moreover, in aging mice, more NPCs differentiate into glia rather than
neurons, compared to younger animals, but we do not know if this happens in humans. Adult neurogenesis is
lower in Alzheimer’s Disease (AD) and it is unknown if this is because more NPCs differentiate into glia or through
other mechanisms. These gaps in knowledge warrant the use of new technologies to investigate cellular lineages
in the human HNN, and molecular regulators of NPCs proliferation, cell fate, differentiation, maturation and
survival. This project aims to identify differentially expressed proteins (DEPs) and genes (DEGs) in the human
HNN, at the regional and single cell level, comparing NA and AD. We will apply our pipeline using high resolution
mass spectrometry for proteomics analysis, and single nuclei (sn) RNA and ATAC (Assay for Transposase-
Accessible Chromatin) sequencing (seq), to identify gene expression and epigenetic changes. In slide-mounted
hippocampus tissue, we will apply Visium (10X Genomics) and our custom-made spatial transcriptomic
technology for anatomical co-mapping of cell-type specific mRNAs and proteins (DBiT-seq). Novel computational
approaches will identify neurogenesis regulators in the human HNN that can be tested in cellular or animal
models. Findings obtained with these “OMICS” approaches will be validated using HighPlex RNAscope®
(ADCBio) and immunofluorescence, and qPCR, Western blots, and ELISA assays, to visualize and quantify DEP
and DEG expression at the single cell and regional level. Our rigorous brain collection methods assure tissue
quality, uniform processing, use of toxicology and neuropathology, and strict clinical inclusion/exclusion criteria.
Groups include: NA subjects (N=100), Braak stage 0-1, age 14-99 yrs., 40 of which (60 years of age and older)
are matched (by age, sex and postmortem interval between death and brain collection) with 40 AD cases (from
the Columbia Taub Institute collection), Braak stage 1 through 4. Aims: 1. Identify HNN DEPs associated with
NA and AD. 2. Identify DEGs in immature and mature neuronal and glial cell populations of the DG in NA and
AD subjects, using sn-RNA and sn-ATAC-seq (10X Genomics). 3. Determine the anatomical localization of cell
expressing DEGs and DEPs associated with NA and AD, using Visium and DBiT-seq. 4. Test correlations
between DEPs and DEGs, and numbers of NPCs and immature neurons and glia in NA and AD.
