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Salisbury, A. J.

Publications and source records attributed to Salisbury, A. J..

4 recordsLinked to original sources

Cortistatin neurons in the prelimbic cortex regulate seizure susceptibility in female mice via BDNF-TrkB signaling

The risk of developing psychiatric disorders, particularly stress-related disorders such as major depressive disorder (MDD) and post-traumatic stress disorder (PTSD), is increased threefold in patients with epilepsy. While this increased risk may arise as a consequence of living with epilepsy, shared neurobiological mechanisms, particularly dysregulation of GABAergic signaling, may also contribute. To investigate this link, we investigated the function of GABAergic neurons co-expressing the neuropeptide cortistatin (CST), which has anticonvulsant effects and is implicated in both MDD and PTSD. Targeting CST+ neurons in the prelimbic cortex (PrL), a rodent brain region that is functionally and anatomically similar to the human dorsal anterior cingulate cortex (dACC), we found that ablating CST+ neurons disrupts context-dependent fear renewal, causes spontaneous convulsive seizures, dramatically increases susceptibility to chemically-induced seizures, and increases anxiety-like phenotypes following stressors. We further show that repeated chemogenetic inhibition of CST+ neurons increases the rate of seizure kindling in female mice, and that disruption of brain derived neurotrophic factor signaling in CST+ neurons phenocopies the effects of acute inhibition. These data support the hypothesis that epilepsy and stress-related psychiatric disorders potentially share common neurobiological mechanisms, and that loss of CST+ neuron function may be a critical feature underlying fear dysregulation and cortical hyperexcitability. HighlightsO_LILoss of prelimbic CST+ neurons disrupts fear renewal, causes anxiety-like symptoms, and induces spontaneous seizures. C_LIO_LIInhibition of prelimbic CST+ by chemogenetics or BDNF inhibition by TrkB increases seizure susceptibility in females only. C_LIO_LICST+ neurons represent a subset of primarily SST and PVALB expressing GABAergic neurons. C_LI

neuroscience↗

Impact of Alzheimer's disease risk factors and local neuromelanin content on the transcriptomic landscape of the human locus coeruleus

The locus coeruleus (LC) is a small noradrenergic nucleus in the dorsal pons that sends projections across the brain regulating sleep, arousal, attention, stress responses, and some forms of cognition. LC neurons show pathology in the earliest stages of Alzheimers disease (AD), including age-related accumulation of hyperphosphorylated tau (pTau) and accelerated loss of neuromelanin (NM) pigmentation. NM-sensitive neuroimaging of the LC predicts previous cognitive decline, clinical severity, and future AD progression. While these findings suggest that the LC plays an etiologic role in AD, the molecular landscape of the LC prior to clinical manifestation of sporadic AD remains largely uncharacterized. This information is critical for developing interventions that preserve LC integrity and function. We performed spatially-resolved transcriptomics on 85 sections of human postmortem LC from N=33 neurotypical middle-aged donors, balanced for epidemiologic AD risk factors including sex, African or European ancestry, and APOE genotype (carriers of the E4/risk or E2/protective alleles). Comparing across APOE genotypes, we find astrocytic gene expression differences proximal to LC neurons. Associating NM content with local gene expression, we show that higher overall APOE gene expression correlates with reduced NM content and an enrichment of NM-associated genes in aging pathways. Unexpectedly, we find enriched LC expression of cholesterol synthesis genes, alongside evidence for lipid synthesis gene regulatory network activity in NM-containing LC specifically, revealing a potential intersection between intrinsic lipid metabolism in LC neurons, NM, and the role of APOE-mediated lipid biology in AD. Together, these data illuminate the molecular features of the human LC at spatial resolution with unprecedented sampling depth, revealing how AD risk factors and NM content influence resilience and susceptibility of this critical brain nucleus to pathology accumulation and degeneration.

neuroscience↗

Prolonged Withdrawal from Escalated Oxycodone is Associated with Increased Expression of Glutamate Receptors in the Rat Hippocampus

People suffering from opioid use disorder (OUD) exhibit cognitive dysfunctions. Here, we investigated potential changes in the expression of glutamate receptors in rat hippocampi at 2 hours and 31 days after the last session of oxycodone self-administration (SA). RNA extracted from the hippocampus was used in quantitative polymerase chain reaction (qPCR) analyses. Rats, given long-access (9 hours per day) to oxycodone (LgA), took significantly more drug than rats exposed to short-access (3 hours per day) (ShA). In addition, LgA rats could be further divided into higher oxycodone taking (LgA-H) or lower oxycodone taking (LgA-L) groups, based on a cut-off of 50 infusions per day. LgA rats, but not ShA, rats exhibited incubation of oxycodone craving. In addition, LgA rats showed increased mRNA expression of GluA1-3 and GluN2a-c subunits as well as Grm3, Grm5, Grm6 and Grm8 subtypes of glutamate receptors after 31 days but not after 2 hours of stopping the SA experiment. Changes in GluA1-3, Grm6, and Grm8 mRNA levels also correlated with increased lever pressing (incubation) after long periods of withdrawal from oxycodone. More studies are needed to elucidate the molecular mechanisms involved in altering the expression of these receptors during withdrawal from oxycodone and/or incubation of drug seeking.

neuroscience↗

Enhancer RNAs are necessary and sufficient for activity-dependent neuronal gene transcription

Genomic enhancer elements regulate gene expression programs important for neuronal fate and function and are implicated in brain disease states. Enhancers undergo bidirectional transcription to generate non-coding enhancer RNAs (eRNAs). However, eRNA function remains controversial. Here, we combined ATAC-Seq and RNA-Seq datasets from three distinct neuronal culture systems in two activity states, enabling genome-wide enhancer identification and prediction of putative enhancer-gene pairs based on correlation of transcriptional output. Notably, stimulus-dependent enhancer transcription preceded mRNA induction, and CRISPR- based activation of eRNA synthesis increased mRNA at paired genes, functionally validating enhancer-gene predictions. Focusing on enhancers surrounding the Fos gene, we report that targeted eRNA manipulation bidirectionally modulates Fos mRNA, and that Fos eRNAs directly interact with the histone acetyltransferase domain of the enhancer-linked transcriptional co-activator CBP. Together, these results highlight the unique role of eRNAs in neuronal gene regulation and demonstrate that eRNAs can be used to identify putative target genes.

neuroscience↗