SRA

Theories of amygdala function are central to our understanding of psychiatric and neurodevelopmental disorders. However, our limited knowledge of the molecular and cellular composition of the amygdala impedes translational research aimed at developing new treatments and interventions. Here, we use single-nucleus RNA-sequencing from multiple amygdala subnuclei in both humans (n=3, Male) and rhesus macaques (n=3, Male) to begin to bridge the gap between preclinical rodent models and human disorders. Our results reveal substantial heterogeneity between regions, even when restricted to inhibitory or excitatory neurons. Consistent with prior work, our data highlight the complexities of individual marker genes for uniquely targeting specific cell-types. Cross-species analyses suggest the rhesus monkey model to be well-suited to understanding the human amygdala, but also identify limitations. For example, we identified a cell-cluster in the ventral lateral nucleus (vLA) of the amygdala that is enriched in humans, relative to rhesus macaques. Additionally, we identify specific cell-clusters with relative enrichment of disorder-related genes. These analyses point to the human-enriched vLa cell-cluster as relevant to ASD, potentially highlighting a vulnerability to neurodevelopmental disorders that has emerged in recent primate evolution. Further, we identified a cluster of cells expressing markers for intercalated cells (ITCs) that is enriched for genes reported in human genome-wide association studies of neuroticism, anxiety disorders, and depressive disorders. Together, these data shed light on the composition of the amygdala and identify specific cell-types that can be prioritized in basic science research to better understand human psychopathology and guide the development of potential treatments Overall design: Subjects include n=3 male rhesus macaques (Macaca Mulatta; age: 3.5-4 years) and n=3 male human donors (Homo Sapiens; Age: 15-19 years, postmortem interval, mean: 23.5 hrs, range: 8-32 hrs). To understand heterogeneity across the primate amygdala, tissue samples were collected from the corresponding areas of the dorsal amygdala Ce-region and the ventral portions of the La-region (vLa) in both primate species. Rhesus tissue was obtained from the California National Primate Research Center. All study procedures were performed in accordance with the guidelines set forth by the University of California Davis Animal Care and Use Committee (IACUC). Human tissue was obtained from the Brain Endowment for Mental Health (BEMH, University of California Davis). All experiments were approved by the Institutional Review Board (IRB) and the IACUC at the University of California, Davis. Under the guidance of expert primate neuroanatomists (CS; AF; JF), 1.5mm tissue biopsy punches at a depth of 2 to 3 mm were used to retrieve samples from Ce and vLA, including embedded ITCs. Single nuclei suspensions were made following minor modifications to 10x genomics demonstrated protocol: Nuclei Isolation from Cell Suspensions and Tissue for Single Cell RNA Sequencing Libraries were prepared by the UC Davis Genomics Core and sequenced on a NovaSeq S4 300 150 bp pair-ended reads (PE150) which targeted a total of 13,149 nuclei for Ce and 8,245 nuclei for vLa across all three Rhesus subjects with 6,973 nuclei for Ce and 9,289 nuclei for vLa across all three Human subjects. Resulting in a total of 67,312 reads per nuclei for Rhesus and 52,378 reads per nuclei for Human