Biology subjects

Coffey, K. R.

Publications and source records attributed to Coffey, K. R..

3 recordsLinked to original sources

bioRxiv2020

RiboTag-Seq Reveals the Activation of the Unfolded Protein Response in Striatal Microglia Induced by Ethanol Withdrawal

Repeated cycles of alcohol intoxication and withdrawal induce profound changes in gene expression that can contribute to the physiological and behavioral consequences of ethanol. Since neuroinflammation is an important consequence of these changes, we used a novel strategy to investigate the impact of repeated cycles of chronic intermittent ethanol vapor and withdrawal on the RNAs actively undergoing translation in microglia in striatum, a key region involved in the relapse to ethanol consumption. We performed deep sequencing of the "translatome" from striatal microglia of male and female RiboTag mice, yielding a snapshot of RNA translation during alcohol intoxication and after 8 hours of withdrawal. Chronic intermittent ethanol produced robust changes in the translatome, with increases in genes and pathways associated with cytokine signaling, indicating increased neuroinflammation and microglial activation. After 8 hours of ethanol withdrawal, many inflammatory pathways remained upregulated and phagocytotic and proapoptotic pathways were increased. Using unbiased network analysis, we identified gene modules that were differentially expressed in ethanol intoxicated vs. withdrawing animals. Genes associated with the unfolded protein response (UPR) were over-represented in one such module after withdrawal, including the transcription factor Ddit3 (CHOP), an important mediator of the UPR. We tested the impact of conditional knockout of CHOP from microglia specifically; following withdrawal from chronic intermittent ethanol, these mice had reduced thermoregulatory disturbances, anxiety-like behavior, and voluntary ethanol consumption compared to wild-type littermates. We conclude that CHOP and the UPR in microglia may be important targets for reducing the impact of withdrawal from chronic ethanol exposure.

neuroscience↗

bioRxiv2020

Stress induces divergent gene expression among lateral habenula efferent pathways

The lateral habenula (LHb) integrates critical information regarding aversive stimuli that shapes decision making and behavioral responses. The three major LHb outputs innervate dorsal raphe nucleus (DRN), ventral tegmental area (VTA), and the rostromedial tegmental nucleus (RMTg). LHb neurons that project to these targets are segregated and nonoverlapping, and this led us to consider whether they have distinct molecular phenotypes and adaptations to stress exposure. In order to capture a time-locked profile of gene expression after repeated forced swim stress, we used intersectional expression of RiboTag in rat LHb neurons and next-gen RNA sequencing to interrogate the RNAs actively undergoing translation from each of these pathways. The "translatome" in the neurons comprising these pathways was similar at baseline, but diverged after stress, especially in the neurons projecting to the RMTg. Using weighted gene co-expression network analysis, we found one module comprising genes downregulated after stress in the RMTg-projecting LHb neurons; there was an overrepresentation of genes associated with phosphoinositide 3 kinase (PI3K) signaling in this module. Reduced PI3K signaling in RMTg-projecting LHb neurons may be a compensatory adaptation that alters the functional balance of LHb outputs to GABAergic vs. monoaminergic neurons following repeated stress exposure.

neuroscience↗

bioRxiv2020

RiboTag-Seq Reveals a Compensatory cAMP Responsive Gene Network in Striatal Microglia induced by Morphine Withdrawal

Microglia have recently been implicated in dependence to opioids. To investigate this directly, we used RNA sequencing of ribosome associated RNAs from striatal microglia (RiboTag-Seq) after the induction of morphine tolerance and then the precipitation of withdrawal by naloxone. We detected large, inverse changes in RNA translation following opioid tolerance and withdrawal, and bioinformatics analysis revealed an intriguing upregulation of cAMP-associated genes that are involved in microglial motility, morphology, and interactions with neurons. Three-dimensional histological reconstruction of microglia revealed changes in process branching and termination following opioid tolerance that were rapidly reversed during withdrawal and were consistent with cAMP effects on microglia morphology. Direct activation of Gi-coupled DREADD receptors in microglia, rather than mimicking the effects of morphine, exacerbated opioid withdrawal. Together these indicate that microglial response to cAMP signaling can mitigate the rapid manifestations of opioid withdrawal.

neuroscience↗