Amygdala-based intrinsic functional connectivity and anxiety disorders in adolescents and young adults

Anxiety disorders (AD) are the most prevalent group of psychiatric disorders in adolescents and young adults. Nevertheless, the pathophysiology of anxiety disorders is still poorly understood. This study investigated differences in the functional connectivity of intrinsic amygdala-based networks of participants with and without AD. Resting state fMRI data were obtained from 18 participants with an AD and 19 healthy comparison individuals. Psychiatric diagnosis was assessed using standardized structured interviews. The comparison between groups was carried out using functional connectivity maps from six seed regions defined using probabilistic maps bilaterally within the amygdala (basolateral, superficial and centromedial amygdala). We found significant between-group differences in five clusters, which showed aberrant functional connectivity with the left basolateral amygdala: right precentral gyrus, right cingulate gyrus, bilateral precuneus, and right superior frontal gyrus in subjects with AD as compared with the comparison subjects. For the comparison subjects, the correlations between the amygdala and the five clusters were either non-significant, or negative. The present study suggests there is an intrinsic disruption in the communication between left basolateral amygdala and a network of brain regions involved with emotion regulation, and with the default mode network in adolescents and young adults with anxiety disorders.

Two waves of proteasome-dependent protein degradation in the hippocampus are required for recognition memory consolidation

Healthy neuronal function and synaptic modification require a concert of synthesis and degradation of proteins. Increasing evidence indicates that protein turnover mediated by proteasome activity is involved in long-term synaptic plasticity and memory. However, its role in different phases of memory remains debated, and previous studies have not examined the possible requirement of protein degradation in recognition memory. Here, we show that the proteasome inhibitor, lactacystin (LAC), infused into the CA1 area of the hippocampus at two specific time points during consolidation, impairs 24-retention of memory for object recognition in rats. Administration of LAC after retrieval did not affect retention. These findings provide the first evidence for a requirement of proteasome activity in recognition memory, indicate that protein degradation in the hippocampus is necessary during selective time windows of memory consolidation, and further our understanding of the role of protein turnover in memory formation.

Alternative splicing of a previously unidentified CFTR exon introduces an in-frame stop codon 5' of the R region

The cystic fibrosis transmembrane conductance regulator (CFTR) has been extensively characterized as the carrier of the basic defect in cystic fibrosis. CFTR is part of a growing family of proteins encoded by a single gene, the variant isoforms of which are generated by alternative splicing or RNA editing. We have analyzed the CFTR mRNA in the region of exons 10-11 in T84 cells and detected an alternatively spliced exon (10b) accounting for about 5% of the CFTR mRNA. The exon 10b found in both the human and mice genomes, introduces an in-frame stop codon. The resulting mRNA is translated into a truncated CFTR protein, identified in T84 cells by immunoprecipitation with the CFTR-specific monoclonal antibody MATG 1061. The insertion of a differentially spliced exon carrying an in-frame stop codon is a novel cellular mechanism for the production of a protein sharing common sequences with another, but having different properties and functions.