Corticosterone Potentiation of Cocaine-Induced Reinstatement of Conditioned Place Preference in Mice is Mediated by Blockade of the Organic Cation Transporter 3

The mechanisms by which stressful life events increase the risk of relapse in recovering cocaine addicts are not well understood. We previously reported that stress, via elevated corticosterone, potentiates cocaine-primed reinstatement of cocaine seeking following self-administration in rats and that this potentiation appears to involve corticosterone-induced blockade of dopamine clearance via the organic cation transporter 3 (OCT3). In the present study, we use a conditioned place preference/reinstatement paradigm in mice to directly test the hypothesis that corticosterone potentiates cocaine-primed reinstatement by blockade of OCT3. Consistent with our findings following self-administration in rats, pretreatment of male C57/BL6 mice with corticosterone (using a dose that reproduced stress-level plasma concentrations) potentiated cocaine-primed reinstatement of extinguished cocaine-induced conditioned place preference. Corticosterone failed to re-establish extinguished preference alone but produced a leftward shift in the dose–response curve for cocaine-primed reinstatement. A similar potentiating effect was observed upon pretreatment of mice with the non-glucocorticoid OCT3 blocker, normetanephrine. To determine the role of OCT3 blockade in these effects, we examined the abilities of corticosterone and normetanephrine to potentiate cocaine-primed reinstatement in OCT3-deficient and wild-type mice. Conditioned place preference, extinction and reinstatement of extinguished preference in response to low-dose cocaine administration did not differ between genotypes. However, corticosterone and normetanephrine failed to potentiate cocaine-primed reinstatement in OCT3-deficient mice. Together, these data provide the first direct evidence that the interaction of corticosterone with OCT3 mediates corticosterone effects on drug-seeking behavior and establish OCT3 function as an important determinant of susceptibility to cocaine use

TCTEX1D2 mutations underlie Jeune asphyxiating thoracic dystrophy with impaired retrograde intraflagellar transport

Tiina Paunio on työryhmän UK10K jäsen.The analysis of individuals with ciliary chondrodysplasias can shed light on sensitive mechanisms controlling ciliogenesis and cell signalling that are essential to embryonic development and survival. Here we identify TCTEX1D2 mutations causing Jeune asphyxiating thoracic dystrophy with partially penetrant inheritance. Loss of TCTEX1D2 impairs retrograde intraflagellar transport (IFT) in humans and the protist Chlamydomonas, accompanied by destabilization of the retrograde IFT dynein motor. We thus define TCTEX1D2 as an integral component of the evolutionarily conserved retrograde IFT machinery. In complex with several IFT dynein light chains, it is required for correct vertebrate skeletal formation but may be functionally redundant under certain conditions.Peer reviewe

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Tissue-specific transcriptome analyses provide new insights into GPCR signalling in adult <i>Schistosoma mansoni</i>

<div><p>Schistosomes are blood-dwelling trematodes with global impact on human and animal health. Because medical treatment is currently based on a single drug, praziquantel, there is urgent need for the development of alternative control strategies. The <i>Schistosoma mansoni</i> genome project provides a platform to study and connect the genetic repertoire of schistosomes to specific biological functions essential for successful parasitism. G protein–coupled receptors (GPCRs) form the largest superfamily of transmembrane receptors throughout the Eumetazoan phyla, including platyhelminths. Due to their involvement in diverse biological processes, their pharmacological importance, and proven druggability, GPCRs are promising targets for new anthelmintics. However, to identify candidate receptors, a more detailed understanding of the roles of GPCR signalling in schistosome biology is essential. An updated phylogenetic analysis of the <i>S</i>. <i>mansoni</i> GPCR genome (GPCR<i>ome</i>) is presented, facilitated by updated genome data that allowed a more precise annotation of GPCRs. Additionally, we review the current knowledge on GPCR signalling in this parasite and provide new insights into the potential roles of GPCRs in schistosome reproduction based on the findings of a recent tissue-specific transcriptomic study in paired and unpaired <i>S</i>. <i>mansoni</i>. According to the current analysis, GPCRs contribute to gonad-specific functions but also to nongonad, pairing-dependent processes. The latter may regulate gonad-unrelated functions during the multifaceted male–female interaction. Finally, we compare the schistosome GPCR<i>ome</i> to that of another parasitic trematode, <i>Fasciola</i>, and discuss the importance of GPCRs to basic and applied research. Phylogenetic analyses display GPCR diversity in free-living and parasitic platyhelminths and suggest diverse functions in schistosomes. Although their roles need to be substantiated by functional studies in the future, the data support the selection of GPCR candidates for basic and applied studies, invigorating the exploitation of this important receptor class for drug discovery against schistosomes but also other trematodes.</p></div

SCF(Pof1)-ubiquitin and its target Zip1 transcription factor mediate cadmium response in fission yeast

Ubiquitin-dependent proteolysis regulates gene expression in many eukaryotic systems. Pof1 is an essential fission yeast F-box protein that is homologous to budding yeast Met30. Temperature-sensitive pof1 mutants display acute growth arrest with small cell size. Extragenic suppressor analysis identified Zip1, a bZIP (basic leucine zipper) transcription factor, as a target for Pof1. We show Zip1 is stabilized in pof1 mutants, Pof1 binds only phosphorylated forms of Zip1, and Zip1 is ubiquitylated in vivo, indicating that Zip1 is a substrate of SCF(Pof1). Genome-wide DNA microarray assay shows that many cadmium-induced genes are under the control of Zip1, suggesting Zip1 plays a role in cadmium response. Consistently, zip1 mutants are hypersensitive to cadmium and unlike wild type, lose cell viability under this stress. Intriguingly, cadmium exposure results in upregulation of Zip1 levels and leads wild-type cells to growth arrest with reduced cell size, reminiscent of pof1 phenotypes. Our results indicate that Zip1 mediates growth arrest in cadmium response, which is essential to maintain viability. Normally growing cells prevent this response through constitutive ubiquitylation and degradation of Zip1 via SCF(Pof1)

Phylogenetic analysis of <i>S</i>. <i>mansoni</i> GPCR genes.

<p>A Bayesian tree of putative <i>S</i>. <i>mansoni</i> GPCRs was inferred with the software tool MrBayes3.2 [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006718#ppat.1006718.ref092" target="_blank">92</a>]. The Tree is rooted between class A and classes B, C, F, and others. Broad subclassifications are indicated, each corresponding to a highly supported node. Gene IDs are coloured according to transcriptomic enrichment. bF, pairing-experienced (bisex) females; bM, pairing-experienced (bisex) males; bT, testes from bM; FLPR, FMRFamide-like Peptide GPCR; GPCR, G protein–coupled receptor; PROF, Platyhelminth-Specific Rhodopsin-like Orphan-Family; sF, pairing-inexperienced (single-sex) females; sM, pairing-inexperienced (single-sex) males; sT, testes from sM.</p

Hierarchical clustering of GPCR genes expressed in adult <i>S</i>. <i>mansoni</i>.

<p>Shown are functional groups to which GPCRs were assigned according to their relative transcript levels in adult <i>S</i>. <i>mansoni</i> obtained by a recent RNA-seq study from Lu et al. [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006718#ppat.1006718.ref032" target="_blank">32</a>]. The heat map shows relative gene expression in all samples, which was calculated by the Z-score method implemented in the heatmap.2 function of the gplots package. Darker color indicates higher expression across all samples, and lighter color indicates lower expression levels (Color Key). The sM-bM-sF group contains GPCR genes with a transcription bias towards males and pairing-inexperienced females, while the “whole worm” group displays a balanced transcription rate among both sexes independently of pairing. Instead of this, the bF and sT-bT groups contain GPCRs that are preferentially transcribed in reproductive organs, namely testis, ovary, or vitellarium. <i>S</i>.<i>m</i>. gene provides Smp numbers for the listed GPCRs of <i>S</i>. <i>mansoni</i>. Existing/missing orthologs in <i>F</i>. <i>hepatica</i> (<i>F</i>. <i>h</i>.) are indicated by +/- (see <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006718#ppat.1006718.s001" target="_blank">S1 Table</a> for details). sM, pairing-inexperienced (single-sex) males; bM, pairing-experienced (bisex) males; sF, pairing-inexperienced (single-sex) females; bF, pairing-experienced (bisex) females; sT, testes from sM; bT, testes from bM; sO, ovaries from sF; bO, ovaries from bF.</p