A key role for nectin-1 in the ventral hippocampus in contextual fear memory

Nectins are cell adhesion molecules that are widely expressed in the brain. Nectin expression shows a dynamic spatiotemporal regulation, playing a role in neural migratory processes during development. Nectin-1 and nectin-3 and their heterophilic trans-interactions are important for the proper formation of synapses. In the hippocampus, nectin-1 and nectin-3 localize at puncta adherentia junctions and may play a role in synaptic plasticity, a mechanism essential for memory and learning. We evaluated the potential involvement of nectin-1 and nectin-3 in memory consolidation using an emotional learning paradigm. Rats trained for contextual fear conditioning showed transient nectin-1—but not nectin-3—protein upregulation in synapse-enriched hippocampal fractions at about 2 h posttraining. The upregulation of nectin-1 was found exclusively in the ventral hippocampus and was apparent in the synaptoneurosomal fraction. This upregulation was induced by contextual fear conditioning but not by exposure to context or shock alone. When an antibody against nectin-1, R165, was infused in the ventral-hippocampus immediately after training, contextual fear memory was impaired. However, treatment with the antibody in the dorsal hippocampus had no effect in contextual fear memory formation. Similarly, treatment with the antibody in the ventral hippocampus did not interfere with acoustic memory formation. Further control experiments indicated that the effects of ventral hippocampal infusion of the nectin-1 antibody in contextual fear memory cannot be ascribed to memory non-specific effects such as changes in anxiety-like behavior or locomotor behavior. Therefore, we conclude that nectin-1 recruitment to the perisynaptic environment in the ventral hippocampus plays an important role in the formation of contextual fear memories. Our results suggest that these mechanisms could be involved in the connection of emotional and contextual information processed in the amygdala and dorsal hippocampus, respectively, thus opening new venues for the development of treatments to psychopathological alterations linked to impaired contextualization of emotions

Loss of the preferential control over the striato-nigral direct pathway by striatal NMDA receptors in a rat model of Parkinson's disease

By using multi-probe microdialysis we previously demonstrated that endogenous glutamate differentially regulates the activity of the striatal output pathways in vivo, through N-methyl-D-aspartate (NMDA) receptors containing the GluN2A or GluN2B subunits. Using the same approach, we presently investigate whether reverse dialysis of NMDA in the striatum differentially affects GABA release in the striatum and in striatal target areas, i.e. globus pallidus (GP) and substantia nigra reticulata (SNr). Moreover, we ask whether this control is altered under parkinsonian conditions. Intrastriatal NMDA perfusion (10 min) evoked GABA release more potently in SNr (1–100 μM) than in other regions (10–100 μM), suggesting preferential control over striato-nigral projection neurons. Intrastriatal NMDA more potently stimulated glutamate levels in the striatum (1–100 μM) and SNr (1–10 μM) than in GP (10 μM). Striatal dopamine denervation with 6-hydroxydopamine caused a leftward shift in the NMDA concentration–response curve. Intrastriatal NMDA elevated GABA levels at 0.1 μM (all regions) and 1 μM (striatum and GP only), but not at higher concentrations, indicating that, compared to naïve animals, the GABA response in SNr was attenuated. Attenuation of the glutamate response was also observed in SNr (NMDA effective only at 0.1 μM). Conversely, the glutamate response in GP was widened (NMDA effective in the 0.1–1 μM range). We conclude that NMDA preferentially stimulates the activity of the striato-nigral direct pathway under physiological conditions. In Parkinson’s disease, dopamine loss compromises the NMDA ability to stimulate striato-nigral neurons, thus shifting the NMDA control towards the striato-pallidal ones

Applicazione della Water Footprint sviluppata dal WF Network: il caso del Pomodorino del Piennolo del Vesuvio DOP

L’agricoltura nei prossimi decenni continuerà ad essere il maggiore utilizzatore della risorsa acqua, richiedendo lo sviluppo di adeguate politiche di gestione e tutela. In tale contesto assume rilievo la discussione sulla valutazione dell’impronta idrica (Water Footprint-WF) e sul confronto fra i diversi metodi mediante la realizzazione di casi applicativi. In questo lavoro si presenta uno studio di WF, effettuato secondo il metodo del WF Network, sul processo di coltivazione del Pomodorino del Piennolo del Vesuvio DOP. Il confronto con analoghi studi di letteratura mostra come il metodo applicato possa fornire informazioni al coltivatore per una riduzione sia dell’uso della risorsa acqua, che degli impatti sulle acque del proprio sistema produttivo. Inoltre, il fattore resa rischia di portare a un valore di WF più elevato per colture tradizionali di qualità rispetto a colture intensive

Dennexin peptides modeled after the homophilic binding sites of the neural cell adhesion molecule (NCAM) promote neuronal survival, modify cell adhesion and impair spatial learning

Neural cell adhesion molecule (NCAM)-mediated cell adhesion results in activation of intracellular signaling cascades that lead to cellular responses such as neurite outgrowth, neuronal survival, and modulation of synaptic activity associated with cognitive processes. The crystal structure of the immunoglobulin (Ig) 1-2-3 fragment of the NCAM ectodomain has revealed novel mechanisms for NCAM homophilic adhesion. The present study addressed the biological significance of the so called dense zipper formation of NCAM. Two peptides, termed dennexinA and dennexinB, were modeled after the contact interfaces between Ig1 and Ig3 and between Ig2 and Ig2, respectively, observed in the crystal structure. Although the two dennexin peptides differed in amino acid sequence, they both modulated cell adhesion, reflected by inhibition of NCAM-mediated neurite outgrowth. Both dennexins also promoted neuronal survival, and the effect of dennexinA was independent of polysialic acid expression. Consistent with the effect of dennexinA on NCAM-mediated adhesion in vitro, the peptide impaired long-term memory retention in rats in the Morris water maze test. Thus, dennexins are novel site-specific pharmacological tools for elucidation of the role of NCAM in a variety of biological processes under normal and pathological conditions

Methylation analysis and HPV genotyping of self-collected cervical samples from women not responding to screening invitation and review of the literature.

AIM OF THE STUDY:To assess the feasibility of partial HPV genotyping and methylation analysis of CADM1, MAL, and miR124-2 genes as triage tests in assaying self-collected cervical samples positive for high-risk HPV on primary screening, and to review the literature regarding host cellular gene methylation analysis of self-collected cervical samples. MATERIAL AND METHODS:Women residing in North-East Italy who had failed to respond to the invitation to participate in an organized population-based program were invited to provide a self-sample. Their stored baseline (self-collected) and follow-up (clinician-collected) cervical samples were included in the study. DNA was extracted from HPV-positive (Qiagen's Hybrid Capture 2, HC2) samples. Partial genotyping with separate detection of HPV types 16 and 18 was performed with a hybrid capture-based method and a quantitative PCR assay. Methylation was assayed with a quantitative methylation-specific PCR. RESULTS:High-risk HPV infection was detected in 48% of baseline and 71% of follow-up HC2-positive samples. Methylation was demonstrated respectively in 15% and 23.5% of baseline and follow-up samples and chiefly involved a single gene (miR124-2). Invalid quantitative PCR results were recorded in 5% of self-collected samples. The specificity of miR124-1, MAL, and CADM1 methylation was 84%, 94%, and 98%, respectively, and the specificity of the three markers combined was 84%. Sensitivity was not estimated due to the lack of CIN2+ samples. The systematic review showed that different methylation assays yield different accuracy values. CONCLUSION:Self-collected samples are suitable for methylation assays included in reflex triage testing. The reproducibility and accuracy of the methylation tests described in the literature should be improved

Effect of nectin-1 on fear memory consolidation tested 7 d after training.

<p>Prior to treatment, there was no difference in the freezing response during CFC. Inhibition of nectin-1 by R165 infusion in the ventral hippocampus immediately after CFC reduced freezing when tested at 7d later (n = 7 animals/group) (n.s., no significant difference; *, p<0.05 vs. control group, two-tailed Student t-test).</p

Effect of context, shock and contextual fear conditioning on nectin-1 (A, B) and nectin-3 (C, D) protein expression in synaptic fractions of ventral and dorsal hippocampi.

<p>The increase of nectin-1 at 2 h after CFC was not seen after context- or shock exposure alone and was restricted to ventral hippocampus (A). Nectin-1 levels in the dorsal hippocampus were not affected 2 h after shock, context or CFC (B). Nectin-3 levels in both ventral- (C) and dorsal hippocampus (D) were unaffected 2 h after context, shock or CFC. Error bars represent standard error of the mean (n = 7–10 animals/group) (*, p<0.05; ** p<0.01 vs. control group indicated by Bonferroni post hoc test).</p

Effect of nectin-1 inhibition on fear memory consolidation.

<p>Prior to treatment, there was no difference in the freezing response during CFC. Inhibition of nectin-1 by R165 infusion in the ventral hippocampus immediately after CFC reduced freezing as measured at 2 and 7 d after contextual fear training (A). This effect was not seen for the dorsal hippocampus (B). Error bars represent standard error of the mean (n = 7 animals/group) (n.s., no significant difference; *, p<0.05: treatment effect R165 vs. control indicated by two-way ANOVA).</p

Effects of nectin-1 inhibition in the ventral hippocampus on anxiety-like behavior (A) and locomotor activity (B).

<p>Inhibition of nectin-1 by infusion of R165 into the ventral hippocampus did not affect time spent in the center, the rim area of the open field as measured 7 d later (A). In addition, locomotor activity in the open field was also not affected by R165 infusion 7 d before (B). Error bars represent standard error of the mean (n = 14 for ACSF-treated animals, n = 19 for R165-treated animals).</p