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Many of the recently identified autism spectrum disorders (ASD) candidate genes code for proteins of excitatory synapses (13-15), suggesting that these disorders may arise from molecular imbalances of synaptic connections. [...], Autism spectrum disorders comprise a range of neurodevelopmental disorders characterized by deficits in social interaction and communication, and by repetitive behaviour (1). Mutations in synaptic proteins such as neuroligins (2,3), neurexins (4), GKAPs/SAPAPs (5) and ProSAPs/ Shanks (6-10) were identified in patients with autism spectrum disorder, but the causative mechanisms remain largely unknown. ProSAPs/ Shanks build large homo- and heteromeric protein complexes at excitatory synapses and organize the complex protein machinery of the postsynaptic density in a laminar fashion (11,12). Here we demonstrate that genetic deletion of ProSAP1/Shank2 results in an early, brain-region-specific upregulation of ionotropic glutamate receptors at the synapse and increased levels of ProSAP2/Shank3. Moreover, ProSAP1/[Shank.sup.-/-] mutants exhibit fewer dendritic spines and show reduced basal synaptic transmission, a reduced frequency of miniature excitatory postsynaptic currents and enhanced JV-methyl-D-aspartate receptor-mediated excitatory currents at the physiological level. Mutants are extremely hyperactive and display profound autistic-like behavioural alterations including repetitive grooming as well as abnormalities in vocal and social behaviours. By comparing the data on ProSAP1/[Shank.sup.-/-] mutants with ProSAP2/ Shank3α[β.sup.-/-] mice, we show that different abnormalities in synaptic glutamate receptor expression can cause alterations in social interactions and communication. Accordingly, we propose that appropriate therapies for autism spectrum disorders are to be carefully matched to the underlying synaptopathic phenotype.

Antibodies normally do not cross the blood-brain barrier (BBB) and cannot bind an intracel-lular cerebral antigen. We demonstrate here for the first time that a new class of antibodies can cross the BBB without treatment. Camelids produce native ho-modimeric heavy-chain antibodies, the paratope being composed of a single-variable domain called VHH. Here, we used recombinant VHH directed against human glial fibrillary acidic protein (GFAP), a specific marker of astrocytes. Only basic VHHs (e.g., pl=9.4) were able to cross the BBB in vitro (7.8 vs. 0% for VHH with pi=7.7). By intracarotid and intravenous injections into live mice, we showed that these basic VHHs are able to cross the BBB in vivo, diffuse into the brain tissue, penetrate into astrocytes, and specifically label GFAP. To analyze their ability to be used as a specific transporter, we then expressed a recombinant fusion protein VHH-green fluorescent protein (GFP). These "fluobodies" specifically labeled GFAP on murine brain sections, and a basic variant (pl=9.3) of the fusion protein VHH-GFP was able to cross the BBB and to label astrocytes in vivo. The potential of VHHs as diagnostic or therapeutic agents in the central nervous system now deserves attention. Li, T., Bourgeois, J.-P., Celli, S., Glacial, F., Le Sourd, A.M., Mecheri, S., Weksler, B., Romero, I., Couraud, P.-O., Rougeon, F., and Lafaye, P. Cell-penetrating anti-GFAP VHH and corresponding fluorescent fusion protein VHH-GFP spontaneously cross the blood-brain barrier and specifically recognize astrocytes: application to brain imaging. [ABSTRACT FROM AUTHOR]

Background: Preexisting cognitive impairment and advanced age are factors that increase the risk of developing postoperative cognitive dysfunction. Because anesthetic agents interfere with cholinergic transmission and as impairment of cholinergic function is associated with cognitive decline, the authors studied how the volatile anesthetic sevoflurane affects exploratory and anxiety-like behavior in young and aged animals with a genetically modified cholinergic system., Methods: Young and aged wild-type and mutant mice lacking the beta2 subunit of the nicotinic cholinergic receptor (beta2KO) were anesthetized for 2 h with 2.6% sevoflurane in oxygen and compared with nonanesthetized controls. Locomotor activity and organization of movement in the open field model were assessed before and 24 h after anesthesia. Locomotor activity and anxiety-like behavior in the elevated plus maze were assessed 24 h after anesthesia. High- and low-affinity nicotinic receptor and cholinergic uptake site densities were evaluated in the hippocampus, amygdala, and forebrain regions using receptor autoradiography., Results: Sevoflurane anesthesia significantly reduced locomotor activity, altered temporospatial organization of trajectories, and increased anxiety-like behavior in young beta2KO mice, whereas no such changes were observed in young wild-type mice. Aged wild-type and beta2KO mice displayed reactions that were similar, but not identical, to the reactions of young mice to sevoflurane anesthesia. However, behavioral changes were not associated with differences in nicotinic receptor or cholinergic uptake site densities., Conclusion: In conclusion, sevoflurane anesthesia altered exploratory and anxiety-like behavior in mice lacking the beta2 nicotinic acetylcholine receptor subunit.