Prenatal Alcohol Exposure Leads to Enhanced Serine 9 Phosphorylation of Glycogen Synthase Kinase‐3β (GSK‐3β) in the Hippocampal Dentate Gyrus of Adult Mouse

Abstract

Background The goal of the present study was to evaluate the expression and serine 9 phosphorylation of glycogen synthase kinase (GSK-3β) within the adult hippocampal dentate gyrus (DG) in a preclinical mouse model of fetal alcohol spectrum disorder (FASD). GSK-3β is a multifunctional kinase that modulates many hippocampal processes affected by gestational alcohol, including synaptic plasticity and adult neurogenesis. GSK-3β is a constitutively active kinase that is negatively regulated by phosphorylation at the serine-9 residue. Methods We utilized a well-characterized limited access “drinking-in-the-dark” paradigm of prenatal alcohol exposure (PAE) and measured p(Ser9)GSK-3β and total GSK-3β within adult dentate gyrus by western blot analysis. In addition, we evaluated the expression pattern of both p(Ser9)GSK-3β and total GSK-3β within the adult hippocampal dentate of PAE and control mice using high resolution confocal microscopy. Results Our findings demonstrate a marked 2.0-fold elevation of p(Ser9)GSK-3β in PAE mice, concomitant with a more moderate 36% increase in total GSK-3β. This resulted in an approximate 63% increase in the p(Ser9)GSK-3β/GSK-3β ratio. Immunostaining revealed robust GSK-3β expression within Cornu Amonis (CA) pyramidal neurons, hilar mossy cells and a subset of GABAergic interneurons, with low levels of expression within hippocampal progenitors and dentate granule cells (DGCs). Conclusions These findings suggest that PAE may lead to a long-term disruption of GSK-3β signaling within the dentate gyrus, and implicate mossy cells, GABAergic interneurons and CA primary neurons as major targets of this dysregulation.

Alcohol Drinking Exacerbates Neural and Behavioral Pathology in the 3xTg-AD Mouse Model of Alzheimer’s Disease

“…Although Tau is phosphorylated by numerous kinases, evidence indicates that glycogen synthase kinase-3 beta (GSK-3β) phosphorylation at Ser199 and Ser202 (pTau-Ser199/202) is a key component of AD pathology and thought to be a viable therapeutic target (Llorens-Martin et al, 2014). Interestingly, GSK-3β is an alcohol-sensitive gene (Wolen et al, 2012) and phospho-protein (Cheng et al, 2017;Liu et al, 2017) in a variety of brain regions, including the HPC of adult mice exposed to prenatal alcohol (Cunningham et al, 2017). Therefore, we asked if Tau phosphorylation at the GSK-3β (Ser199/202) site is altered by alcohol drinking in 3xTg-AD mice, which would indicate a potential target of alcohol.…”

Resistance of Postnatal Hippocampal Neurogenesis to Alcohol Toxicity in a Third Trimester‐Equivalent Mouse Model of Gestational Alcohol Exposure

“…Administration of tamoxifen daily for 5 days during young adulthood (PND 35 to PND 39) labeled a cohort of tdTom + aDGCs that was situated primarily within the inner third of the dentate granule cell layer, as previously described by us and others (Cunningham et al., ; Kajimoto et al., ; Lagace et al., ; Mathews et al., ). Prior studies with rats have demonstrated a persistent deficit in adult neurogenesis following early postnatal EtOH binge‐like exposures using intragastric gavage between PND 4 and 10 (BACs ~315 mg%), which could be reversed by a sequential wheel‐running and EE regimen (Hamilton et al., , ; Klintsova et al., ).…”

“…Importantly, we found that early postnatal EtOH exposure also had no impact on the neurogenic response to EE. This result is surprising, since we have previously demonstrated a robust impairment of EE‐mediated neurogenesis in adult mice exposed to moderate doses (80 to 120 mg/dl) of EtOH throughout gestation (Choi et al., ; Cunningham et al., ; Kajimoto et al., ). The impaired EE‐mediated neurogenesis in gestationally exposed mice is also associated with a significant impairment of pattern discrimination learning (Kajimoto et al., ) and with a compensatory increase in the frequency of excitatory synaptic activity in surviving aDGCs (Kajimoto et al., ).…”

“…007909; Madisen et al., ). Tamoxifen administration results in Cre‐mediated recombination and tdTom reporter expression within nestin + hippocampal progenitors and downstream progeny (Cunningham et al., ; Lagace et al., ; Li et al., ; Newville et al., ). All animal procedures were approved by the University of New Mexico Health Sciences Center Institutional Animal Care and Use Committee guidelines per the NIH Animal Welfare Regulations and Public Health Service Policy on Human Care and Use of Laboratory Animals.…”

“…We utilized a well‐characterized Cre‐loxP genetic labeling approach in NestinCreER T2 :tdTomato bitransgenic mice to identify newborn DGCs. These mice harbor a tamoxifen‐inducible tdTomato reporter for indelible labeling of newborn DGCs in vivo (Cunningham et al., ; Gustus et al., ). Surprisingly, we found that moderate EtOH exposure during the early postnatal period impacts neither the production nor the survival of dDGCs, and has no effect on the production of aDGCs or the ability to mount a neurogenic response to EE in adulthood.…”