GSE174085
Single-Cell Transcriptomics of hypothalamic CRH-expressing neurons informs mechanisms by which Early-Life Adversity sculpts stress-responses enduringly
Mental and cognitive health, as well as vulnerability to neuropsychiatric disorders, involve the interplay of genes with the environment during sensitive developmental periods. Genetic and environmental factors contribute to the development and maturation of neurons, synapses, and the resulting brain circuits. Within the hypothalamus, early-life experiences cause changes in the number of excitatory synapses onto corticotropin-releasing hormone (CRH)-expressing neurons in the paraventricular nucleus (PVN). Further, such synaptic changes suffice to induce enduring epigenomic changes within these cells, influencing programs of gene expression. However, the epigenetic mechanisms by which early-life experiences orchestrate transcriptional programs within individual CRH-expressing neurons, with enduring functional consequences, remain unknown. We utilize animal models of an impoverished environment and unpredictable maternal care (in a limited bedding and nesting [LBN] paradigm), which provokes major alterations in cognitive and emotional outcomes. We are focused on the change in gene expression profiles of stress-sensitive CRH-neurons in the PVN following early-life adversity (ELA). Because of the known heterogeneity of CRH-expressing neuronal populations, we are using single-cell RNA sequencing (RNA-seq) to determine differential gene expression associated with early-life adversity and establish the upstream mechanisms and downstream consequences. We found that CRH-expressing populations of neurons in the PVN can be clustered by both their gene expression profiles as well as by their neurotransmitter phenotype. ELA significantly modified gene expression programs in some neuronal clusters more than others, reducing programs of neuronal development and differentiation and enhancing gene families involved in responses to stress and inflammation. The use of single-cell transcriptomics revealed that ELA impacts gene expression profiles in a cell-type specific manner, with distinctive influence on the different clusters and subpopulations of CRH neurons.  Overall design: Compare control vs early life adversity conditions in mice during a sensitive time in brain development