Neuregulin 1 and susceptibility to schizophrenia

To access full text version of this article. Please click on the hyperlink "View/Open" at the bottom of this pageThe cause of schizophrenia is unknown, but it has a significant genetic component. Pharmacologic studies, studies of gene expression in man, and studies of mouse mutants suggest involvement of glutamate and dopamine neurotransmitter systems. However, so far, strong association has not been found between schizophrenia and variants of the genes encoding components of these systems. Here, we report the results of a genomewide scan of schizophrenia families in Iceland; these results support previous work, done in five populations, showing that schizophrenia maps to chromosome 8p. Extensive fine-mapping of the 8p locus and haplotype-association analysis, supplemented by a transmission/disequilibrium test, identifies neuregulin 1 (NRG1) as a candidate gene for schizophrenia. NRG1 is expressed at central nervous system synapses and has a clear role in the expression and activation of neurotransmitter receptors, including glutamate receptors. Mutant mice heterozygous for either NRG1 or its receptor, ErbB4, show a behavioral phenotype that overlaps with mouse models for schizophrenia. Furthermore, NRG1 hypomorphs have fewer functional NMDA receptors than wild-type mice. We also demonstrate that the behavioral phenotypes of the NRG1 hypomorphs are partially reversible with clozapine, an atypical antipsychotic drug used to treat schizophrenia

Cell cycle dependent methylation of Dam1 contributes to kinetochore integrity and faithful chromosome segregation.

The kinetochore, a megadalton structure composed of centromeric (CEN) DNA and protein complexes, is required for faithful chromosome segregation in eukaryotes. The evolutionarily conserved Dam1/DASH complex (Ska1 in metazoans) is one of the essential protein sub-complexes of the budding yeast kinetochore. Previous studies showed that methylation of lysine residue 233 in Dam1 by Set1 is important for haploid growth as mutation of lysine 233 to alanine results in lethality. In this study, we report that Set1-mediated cell cycle dependent Dam1 lysine methylation contributes to kinetochore assembly and chromosomal stability. Our results show that Dam1 methylation is cell cycle regulated with the highest levels of methylation in metaphase. Consistent with these results, co-immunoprecipitation experiments revealed an interaction between Dam1 with Set1 in metaphase cells. Set1 has been shown to colocalize with Jhd2, a histone lysine demethylase which demethylates Set1-methylated histones. Affinity purification-based mass spectroscopy of Jhd2 associated proteins identified seven of the ten subunits of the Dam1 complex; an association of Jhd2 with non-histone proteins, such as Dam1 has not been previously reported. We confirmed the interaction of Jhd2 with Dam1 and showed that cells overexpressing JHD2 exhibit reduced levels of methylated lysine in Dam1 in wild type and UBP8 deletion strains, growth defects in kinetochore mutants, reduced levels of kinetochore proteins at CEN chromatin, defects in kinetochore biorientation and chromosome missegregation. In summary, we have shown that cell cycle dependent methylation of Dam1 plays a crucial role in the maintenance of kinetochore assembly for faithful chromosome segregation

Loss of Ubiquitin-Specific Peptidase 18 Destabilizes 14-3-3ζ Protein and Represses Lung Cancer Metastasis

Cancer metastasis is a major cause of cancer-related mortality. Strategies to reduce metastases are needed especially in lung cancer, the most common cause of cancer mortality. We previously reported increased ubiquitin-specific peptidase 18 (USP18) expression in lung and other cancers. Engineered reduction of USP18 expression repressed lung cancer growth and promoted apoptosis. This deubiquitinase (DUB) stabilized targeted proteins by removing the complex interferon-stimulated gene 15 (ISG15). This study explores if the loss of USP18 reduced lung cancer metastasis. USP18 knock-down in lung cancer cells was independently achieved using small hairpin RNAs (shRNAs) and small interfering RNAs (siRNAs). USP18 knock-down reduced lung cancer growth, wound-healing, migration, and invasion versus controls (P \u3c .001) and markedly decreased murine lung cancer metastases (P \u3c .001). Reverse Phase Protein Arrays (RPPAs) in shRNA knock-down lung cancer cells showed that 14-3-3ζ protein was regulated by loss of USP18. ISG15 complexed with 14-3-3ζ protein reducing its stability. Survival in lung adenocarcinomas (P \u3c .0015) and other cancers was linked to elevated 14-3-3ζ expression as assessed by The Cancer Genome Atlas (TCGA). The findings were confirmed and extended using 14-3-3ζ immunohistochemical assays of human lung cancer arrays and syngeneic murine lung cancer metastasis models. A direct 14-3-3ζ role in controlling lung cancer metastasis came from engineered 14-3-3ζ knock-down in lung cancer cell lines and 14-3-3ζ rescue experiments that reversed migration and invasion inhibition. Findings presented here revealed that USP18 controlled metastasis by regulating 14-3-3ζ expression. These data provide a strong rationale for developing a USP18 inhibitor to combat metastases

HLA class I signal peptide polymorphism determines the level of CD94/NKG2–HLA-E-mediated regulation of effector cell responses

Human leukocyte antigen (HLA)-E binds epitopes derived from HLA-A, HLA-B, HLA-C and HLA-G signal peptides (SPs) and serves as a ligand for CD94/NKG2A and CD94/NKG2C receptors expressed on natural killer and T cell subsets. We show that among 16 common classical HLA class I SP variants, only 6 can be efficiently processed to generate epitopes that enable CD94/NKG2 engagement, which we term ‘functional SPs’. The single functional HLA-B SP, known as HLA-B/−21M, induced high HLA-E expression, but conferred the lowest receptor recognition. Consequently, HLA-B/−21M SP competes with other SPs for providing epitope to HLA-E and reduces overall recognition of target cells by CD94/NKG2A, calling for reassessment of previous disease models involving HLA-B/−21M. Genetic population data indicate a positive correlation between frequencies of functional SPs in humans and corresponding cytomegalovirus mimics, suggesting a means for viral escape from host responses. The systematic, quantitative approach described herein will facilitate development of prediction algorithms for accurately measuring the impact of CD94/NKG2–HLA-E interactions in disease resistance/susceptibility

Transient APC/C inactivation by mTOR boosts glycolysis during cell cycle entry

Mammalian cells entering the cell cycle favour glycolysis to rapidly generate ATP and produce the biosynthetic intermediates that are required for rapid biomass accumulation1. Simultaneously, the ubiquitin-ligase anaphase-promoting complex/cyclosome and its coactivator CDH1 (APC/CCDH1) remains active, allowing origin licensing and blocking premature DNA replication. Paradoxically, glycolysis is reduced by APC/CCDH1 through the degradation of key glycolytic enzymes2, raising the question of how cells coordinate these mutually exclusive events to ensure proper cell division. Here we show that cells resolve this paradox by transiently inactivating the APC/C during cell cycle entry, which allows a transient metabolic shift favouring glycolysis. After mitogen stimulation, rapid mTOR-mediated phosphorylation of the APC/C adapter protein CDH1 at the amino terminus causes it to partially dissociate from the APC/C. This partial inactivation of the APC/C leads to the accumulation of PFKFB3, a rate-limiting enzyme for glycolysis, promoting a metabolic shift towards glycolysis. Delayed accumulation of phosphatase activity later removes CDH1 phosphorylation, restoring full APC/C activity, and shifting cells back to favouring oxidative phosphorylation. Thus, cells coordinate the simultaneous demands of cell cycle progression and metabolism through an incoherent feedforward loop, which transiently inhibits APC/C activity to generate a pulse of glycolysis that is required for mammalian cell cycle entry

A structure-based designed small molecule depletes hRpn13Pru and a select group of KEN box proteins

Proteasome subunit hRpn13 is partially proteolyzed in certain cancer cell types to generate hRpn13Pru by degradation of its UCHL5/Uch37-binding DEUBAD domain and retention of an intact proteasome- and ubiquitin-binding Pru domain. By using structure-guided virtual screening, we identify an hRpn13 binder (XL44) and solve its structure ligated to hRpn13 Pru by integrated X-ray crystallography and NMR to reveal its targeting mechanism. Surprisingly, hRpn13Pru is depleted in myeloma cells following treatment with XL44. TMT-MS experiments reveal a select group of off-targets, including PCNA clamp-associated factor PCLAF and ribonucleoside-diphosphate reductase subunit M2 (RRM2), that are similarly depleted by XL44 treatment. XL44 induces hRpn13-dependent apoptosis and also restricts cell viability by a PCLAF-dependent mechanism. A KEN box, but not ubiquitination, is required for XL44-induced depletion of PCLAF. Here, we show that XL44 induces ubiquitin-dependent loss of hRpn13Pru and ubiquitin-independent loss of select KEN box containing proteins

Multiplatform metabolomic interlaboratory study of a whole human stool candidate reference material from omnivore and vegan donors.

INTRODUCTION: Human metabolomics has made significant strides in understanding metabolic changes and their implications for human health, with promising applications in diagnostics and treatment, particularly regarding the gut microbiome. However, progress is hampered by issues with data comparability and reproducibility across studies, limiting the translation of these discoveries into practical applications. OBJECTIVES: This study aims to evaluate the fit-for-purpose of a suite of human stool samples as potential candidate reference materials (RMs) and assess the state of the field regarding harmonizing gut metabolomics measurements. METHODS: An interlaboratory study was conducted with 18 participating institutions. The study allowed for the use of preferred analytical techniques, including liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC-MS), and nuclear magnetic resonance (NMR). RESULTS: Different laboratories used various methods and analytical platforms to identify the metabolites present in human stool RM samples. The study found a 40% to 70% recurrence in the reported top 20 most abundant metabolites across the four materials. In the full annotation list, the percentage of metabolites reported multiple times after nomenclature standardization was 36% (LC-MS), 58% (GC-MS) and 76% (NMR). Out of 9,300 unique metabolites, only 37 were reported across all three measurement techniques. CONCLUSION: This collaborative exercise emphasized the broad chemical survey possible with multi-technique approaches. Community engagement is essential for the evaluation and characterization of common materials designed to facilitate comparability and ensure data quality underscoring the value of determining current practices, challenges, and progress of a field through interlaboratory studies

Particulate matter exposure during pregnancy is associated with birth weight, but not gestational age, 1962-1992: a cohort study

<p>Abstract</p> <p>Background</p> <p>Exposure to air pollutants is suggested to adversely affect fetal growth, but the evidence remains inconsistent in relation to specific outcomes and exposure windows.</p> <p>Methods</p> <p>Using birth records from the two major maternity hospitals in Newcastle upon Tyne in northern England between 1961 and 1992, we constructed a database of all births to mothers resident within the city. Weekly black smoke exposure levels from routine data recorded at 20 air pollution monitoring stations were obtained and individual exposures were estimated via a two-stage modeling strategy, incorporating temporally and spatially varying covariates. Regression analyses, including 88,679 births, assessed potential associations between exposure to black smoke and birth weight, gestational age and birth weight standardized for gestational age and sex.</p> <p>Results</p> <p>Significant associations were seen between black smoke and both standardized and unstandardized birth weight, but not for gestational age when adjusted for potential confounders. Not all associations were linear. For an increase in whole pregnancy black smoke exposure, from the 1^st(7.4 μg/m³) to the 25^th(17.2 μg/m³), 50^th(33.8 μg/m³), 75^th(108.3 μg/m³), and 90^th(180.8 μg/m³) percentiles, the adjusted estimated decreases in birth weight were 33 g (SE 1.05), 62 g (1.63), 98 g (2.26) and 109 g (2.44) respectively. A significant interaction was observed between socio-economic deprivation and black smoke on both standardized and unstandardized birth weight with increasing effects of black smoke in reducing birth weight seen with increasing socio-economic disadvantage.</p> <p>Conclusions</p> <p>The findings of this study progress the hypothesis that the association between black smoke and birth weight may be mediated through intrauterine growth restriction. The associations between black smoke and birth weight were of the same order of magnitude as those reported for passive smoking. These findings add to the growing evidence of the harmful effects of air pollution on birth outcomes.</p

Abstract 215: Characterization by mass spectrometry of protein kinase C substrates differentially phosphorylated in LNCaP cells in response to phorbol ester and bryostatin 1 treatment

Abstract Bryostatin 1 (bryo 1) is a natural product of therapeutic interest for cancer and Alzheimer disease. Its unique behavior as a protein kinase C activator that paradoxically antagonizes many but not all phorbol ester responses has led to intense interest in its mechanism of action. Recently, using microarray analysis in two different cellular systems (LNCaP prostate cancer and U937 leukemia cell lines) where the typical phorbol ester PMA and bryo 1 have different biology, we have shown that a core mechanism contributing to the unique biology of bryo 1 is transiency of action resulting in a variable extent of decreased or missing late responses. We have excluded that there is a class of genes whose transcription is uniquely regulated at early times by bryo 1. In continuing to explore the mechanisms underlying the variable transiency of the responses by bryo 1 we have evaluated the substrates phosphorylated after treatment with PMA and bryo 1. Since PMA and bryo 1 induce differential subcellular localization of PKCs, they should result in differential access to substrates and consequent differences in the pattern of substrate phosphorylation. Whole cell lysates of LNCaP cells treated for 30 min with fully effective doses (100 nM) of PMA and bryo 1 and with DMSO as vehicle control were subjected to mass spectroscopic analysis. The comprehensive analysis identified several thousand phosphopeptides after drug treatment including the expected phosphopeptides for ERK2 (S185, Y187) and PKCdelta (S299, S302, S304). Many of peptides were similarly phosphorylated in response to both drugs (e.g. S641/S646 of Fam129B, S310 of actin-related protein 2/3 complex subunit 1B, S876 of RhoGEF and pleckstrin domain-containing protein 2, or multiple previously unknown sites for PKD1 (S239, S247), while a limited number were differentially phosphorylated. PMA specific phosphorylations included PKCdelta at Y313, mTOR at T2471, MAP4 at S624 and/or T627, E3 ubiquitin-protein ligases ZNRF2 at S82 and HUWE1 at S3818. Bryo 1 specific phosphorylations included BCL2-like 13 at S303, TOM1L2 at S424, and MAP2K2 in the T17, T25, S26 region. Selected specific phosphorylations are being validated using phostag gels, a method that enables the separation of phosphorylated proteins from their non-phosphorylated counterparts on SDS-gels. The identification of PKC substrates that are differentially phosphorylated by bryo 1 should both facilitate screening of other ligands capturing the biological behavior of bryo 1 as well as further illuminate the specifics of the pathways downstream of PKC activation by these differently acting ligands. Citation Format: Noemi Kedei, Sudipto Das, Thorkell Andresson, Peter M. Blumberg. Characterization by mass spectrometry of protein kinase C substrates differentially phosphorylated in LNCaP cells in response to phorbol ester and bryostatin 1 treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 215. doi:10.1158/1538-7445.AM2017-215</jats:p