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Dean, T.

Publications and source records attributed to Dean, T..

2 recordsLinked to original sources

Adolescent intermittent ethanol exposure induces sex-specific and time-dependent changes in affective behaviors and metabolomic profiles.

Given the adverse effects of adolescent binge alcohol consumption in humans, the present work explores the lasting behavioral and metabolomic impacts following adolescent binge ethanol exposure. Here we determine short- and long-term changes in affective behaviors and metabolomic profiles in male and female adolescent binge ethanol-exposed mice. Male and female C57BL/6J mice were exposed to adolescent intermittent ethanol (AIE) as a model of binge ethanol exposure using intermittent vapor inhalation from postnatal day (PND) 28-42. Mice were tested in a battery of behavioral tests and metabolomic analyses were conducted following short-term and long-term withdrawal from AIE exposure. Mice were tested for affective behaviors using the open field test (OFT), the light/dark test (LDT), and the tail suspension test (TST) one week following AIE exposure from PND 49-53 and again from PND 91-95. Serum samples were collected on PND 43, corresponding to 24 hours after the last exposure, fecal samples were collected during each OFT, and liver samples were collected approximately 80 days after AIE exposure for metabolomic analysis. We show modest incubation of behavioral differences in anxiety-like behavior in males after adolescent binge ethanol exposure; an effect that was absent in female mice. In contrast, metabolomic differences in male mice that were more pronounced shortly after adolescent binge ethanol exposure waned as time progressed since last exposure. Male mice appear to be more susceptible to the persistent changes in adolescent binge ethanol exposure that varies over time. It is possible that short-term metabolomic changes may predict long-term behavioral changes in affective behaviors. Contribution to the field statementAdolescent binge alcohol exposure causes long-lasting changes in behavior, however the underlying biology mediating these changes have not readily been assessed in a sex-specific manner. Metabolomic assays are a powerful tool that can be used as biomarkers to determine changes in biological pathways that are linked to specific behavioral phenotypes. Here we explored the relationship between adolescent binge alcohol exposure, changes in anxiety-like behavior, and metabolomic profiles in male and female C57BL/6J mice. We find robust changes in metabolomic profiles following short-term withdrawal in male mice exposed to binge alcohol during adolescence. We also see modest changes in anxiety-like behavior following long-term withdrawal. Although female mice did not show any robust changes in anxiety-like behavior nor global changes in metabolomic profiles, in both sexes we do observe persistent changes in some amino acids, which may serve as specific biomarkers associated with changes in alcohol-induced behavioral changes. These data add to the field by conducting a novel longitudinal study following male and female mice from adolescence to early adulthood and measuring physiological biomarkers (metabolomics) coupled with behavioral changes following binge ethanol exposure.

neuroscience↗

Regulation of intracellular cAMP levels in osteocytes by mechano-sensitive focal adhesion kinase via PDE8A

Osteocytes are the primary mechano-sensitive cell type in bone. Mechanical loading is sensed across the dendritic projections of osteocytes leading to transient reductions in focal adhesion kinase (FAK) activity. Knowledge regarding the signaling pathways downstream of FAK in osteocytes is incomplete. We performed tyrosine-focused phospho-proteomic profiling in osteocyte-like Ocy454 cells to identify FAK substrates. Gs, parathyroid hormone receptor (PTH1R), and phosphodiesterase 8A (PDE8A), all proteins associated with cAMP signaling, were found as potential FAK targets based on their reduced tyrosine phosphorylation in both FAK- deficient or FAK inhibitor treated cells. Real time monitoring of intracellular cAMP levels revealed that FAK pharmacologic inhibition or gene deletion increased basal and GPCR ligand-stimulated cAMP levels and downstream phosphorylation of protein kinase A substrates. Mutating FAK phospho-acceptor sites in Gs and PTH1R had no effect on PTH- or FAK inhibitor-stimulated cAMP levels. Since FAK inhibitor treatment augmented cAMP levels even in the presence of forskolin, we focused on potential FAK substrates downstream of cAMP generation. Indeed, PDE8A inhibition mimicked FAK inhibition at the level of increased cAMP, PKA activity, and expression of cAMP-regulated target genes. In vitro kinase assay showed that PDE8A is directly phosphorylated by FAK while immunoprecipitation assays revealed intracellular association between FAK and PDE8A. Thus, FAK inhibition in osteocytes acts synergistically with signals that activate adenylate cyclase to increase intracellular cAMP. Mechanically-regulated FAK can modulate intracellular cAMP levels via effects on PDE8A. These data suggest a novel signal transduction mechanism that mediates crosstalk between mechanical and cAMP-linked hormonal signaling in osteocytes.

molecular biology↗