Rationale Stress experiences have been shown to be a risk factor for alcohol abuse in humans; however, a reliable mouse model using episodic social stress has yet to be developed. Objectives The current studies investigated the effects of mild and moderate social defeat protocols on plasma corticosterone, voluntary alcohol drinking, and motivation to drink alcohol. Methods Outbred CFW mice were socially defeated for 10 days during which the intruder mouse underwent mild (15 bites: mean = 1.5 min), or moderate (30 bites: mean = 3.8 min) stress. Plasma corticosterone was measured on days 1 and 10 of the defeat. Ethanol drinking during continuous access to alcohol was measured 10 days following the defeat or 10 days prior to, during and 20 days after the defeat. Motivation to drink was determined using a PR operant conditioning schedule during intermittent access to ethanol. Results Plasma corticosterone was elevated in both stress groups on days 1 and 10. Ethanol consumption and preference following moderate social stress was higher than both the mild stress group and controls. Mice with previously acquired ethanol drinking showed decreased ethanol consumption during the moderate stress followed by an increase 20 days post-defeat. Moderately stressed mice also showed escalated ethanol intake (11g/kg/day) and ethanol self-administration during a schedule of intermittent access to alcohol. Conclusion Social defeat experiences of moderate intensity and duration led to increased ethanol drinking and preference in CFW mice. Ongoing work investigates the interaction between glucocorticoids and dopaminergic systems as neural mechanisms for stress-escalated alcohol consumption.

Reduction of native prion protein (PrP) levels in the brain is an attractive strategy for the treatment or prevention of human prion disease. Clinical development of any PrP-reducing therapeutic will require an appropriate pharmacodynamic biomarker: a practical and robust method for quantifying PrP, and reliably demonstrating its reduction in the central nervous system (CNS) of a living patient. Here we evaluate the potential of ELISA-based quantification of human PrP in human cerebrospinal fluid (CSF) to serve as a biomarker for PrP-reducing therapeutics. We show that CSF PrP is highly sensitive to plastic adsorption during handling and storage, but its loss can be minimized by the addition of detergent. We find that blood contamination does not affect CSF PrP levels, and that CSF PrP and hemoglobin are uncorrelated, together suggesting that CSF PrP is CNS derived, supporting its relevance for monitoring the tissue of interest and in keeping with high PrP abundance in brain relative to blood. In a cohort with controlled sample handling, CSF PrP exhibits good within-subject test–retest reliability (mean coefficient of variation, 13% in samples collected 8–11 wk apart), a sufficiently stable baseline to allow therapeutically meaningful reductions in brain PrP to be readily detected in CSF. Together, these findings supply a method for monitoring the effect of a PrP-reducing drug in the CNS, and will facilitate development of prion disease therapeutics with this mechanism of action.

The capacity of certain adeno-associated virus (AAV) vectors to cross the blood–brain barrier after intravenous delivery offers a unique opportunity for noninvasive brain delivery. However, without a well-tailored system, the use of a peripheral route injection may lead to undesirable transgene expression in nontarget cells or organs. To refine this approach, the present study characterizes the transduction profiles of new self-complementary AAV9 (scAAV9) expressing the green fluorescent protein (GFP) either under an astrocyte (glial fibrillary acidic (GFA) protein) or neuronal (Synapsin (Syn)) promoter, after intravenous injection of adult mice (2 × 1013 vg/kg). ScAAV9-GFA-GFP and scAAV9-Syn-GFP robustly transduce astrocytes (11%) and neurons (17%), respectively, without aberrant expression leakage. Interestingly, while the percentages of GFP-positive astrocytes with scAAV9-GFA-GFP are similar to the performances observed with scAAV9-CBA-GFP (broadly active promoter), significant higher percentages of neurons express GFP with scAAV9-Syn-GFP. GFP-positive excitatory as well as inhibitory neurons are observed, as well as motor neurons in the spinal cord. Additionally, both activated (GFAP-positive) and resting astrocytes (GFAP-negative) express the reporter gene after scAAV9-GFA-GFP injection. These data thoroughly characterize the gene expression specificity of AAVs fitted with neuronal and astrocyte-selective promoters after intravenous delivery, which will prove useful for central nervous system (CNS) gene therapy approaches in which peripheral expression of transgene is a concern.