Thalamocortical and corticothalamic pathways differentially contribute to goal-directed behaviors in the rat.

Highly distributed neural circuits are thought to support adaptive decision-making in volatile and complex environments. Notably, the functional interactions between prefrontal and reciprocally connected thalamic nuclei areas may be important when choices are guided by current goal value or action-outcome contingency. We examined the functional involvement of selected thalamocortical and corticothalamic pathways connecting the dorsomedial prefrontal cortex (dmPFC) and the mediodorsal thalamus (MD) in the behaving rat. Using a chemogenetic approach to inhibit projection-defined dmPFC and MD neurons during an instrumental learning task, we show that thalamocortical and corticothalamic pathways differentially support goal attributes. Both pathways participate in adaptation to the current goal value, but only thalamocortical neurons are required to integrate current causal relationships. These data indicate that antiparallel flow of information within thalamocortical circuits may convey qualitatively distinct aspects of adaptive decision-making and highlight the importance of the direction of information flow within neural circuits.

Ebola virus vaccine: benefit and risks of adenovirus-based vectors.

In 2014, an outbreak of Ebola virus spread rapidly in West Africa. The epidemic killed more than 10,000 people and resulted in transmissions outside the endemic countries. WHO hopes for effective vaccines by the end of 2015. Numerous vaccine candidates have been proposed, and several are currently being evaluated in humans. Among the vaccine candidates are vectors derived from adenovirus (Ad). Despite previous encouraging preclinical and Phase I/II trials, Ad vectors used in three Phase II trials targeting HIV were prematurely interrupted because of the lack of demonstrated efficacy. The vaccine was not only ineffective but also led to a higher rate of HIV acquisition. In this context, the authors discuss the potential benefits, risks and impact of using Ad-derived vaccines to control Ebola virus disease.

Gene transfer may be preventive but not curative for a lysosomal transport disorder.

Cystinosis belongs to a growing class of lysosomal storage disorders (LSDs) caused by defective transmembrane proteins. The causative CTNS gene encodes the lysosomal cystine transporter, cystinosin. Currently the aminothiol cysteamine is the only drug available for reducing cystine storage but this treatment has non-negligible side effects and administration constraints. In this study, for the first time, we report viral vector-mediated CTNS gene transfer and evaluate the feasibility of this strategy as a complementary treatment. Initially, we transduced human CTNS(-/-) fibroblast cell lines and primary murine Ctns(-/-) hepatocyte cultures in vitro and demonstrated that gene transfer can reduce cystine storage. Because of age-related increase in cystine levels, we transduced hepatocytes from young (/=5 months of age) mice. Our in vitro data suggested that the efficiency of correction was age-dependent. We tested these observations in vivo: short-term (1 week) and long-term (4 weeks) CTNS-transduction significantly reduced hepatic cystine levels in young, but not older, Ctns(-/-) mice. Our data provide the proof-of-concept that gene transfer is feasible for correcting defective lysosomal transport, but suggest that, in the case of cystinosis, it could be preventive but not curative in some tissues.