Mmp12 Is Translationally Regulated in Macrophages during the Course of Inflammation

Despite the importance of rapid adaptive responses in the course of inflammation and the notion that post-transcriptional regulation plays an important role herein, relevant translational alterations, especially during the resolution phase, remain largely elusive. In the present study, we analyzed translational changes in inflammatory bone marrow-derived macrophages upon resolution-promoting efferocytosis. Total RNA-sequencing confirmed that apoptotic cell phagocytosis induced a pro-resolution signature in LPS/IFNγ-stimulated macrophages (Mϕ). While inflammation-dependent transcriptional changes were relatively small between efferocytic and non-efferocytic Mϕ; considerable differences were observed at the level of de novo synthesized proteins. Interestingly, translationally regulated targets in response to inflammatory stimuli were mostly downregulated, with only minimal impact of efferocytosis. Amongst these targets, pro-resolving matrix metallopeptidase 12 (Mmp12) was identified as a translationally repressed candidate during early inflammation that recovered during the resolution phase. Functionally, reduced MMP12 production enhanced matrix-dependent migration of Mϕ. Conclusively, translational control of MMP12 emerged as an efficient strategy to alter the migratory properties of Mϕ throughout the inflammatory response, enabling Mϕ migration within the early inflammatory phase while restricting migration during the resolution phase.

Hypoxia-altered cholesterol homeostasis enhances the expression of interferon-stimulated genes upon SARS-CoV-2 infections in monocytes

Hypoxia contributes to numerous pathophysiological conditions including inflammation-associated diseases. We characterized the impact of hypoxia on the immunometabolic cross-talk between cholesterol and interferon (IFN) responses. Specifically, hypoxia reduced cholesterol biosynthesis flux and provoked a compensatory activation of sterol regulatory element-binding protein 2 (SREBP2) in monocytes. Concomitantly, a broad range of interferon-stimulated genes (ISGs) increased under hypoxia in the absence of an inflammatory stimulus. While changes in cholesterol biosynthesis intermediates and SREBP2 activity did not contribute to hypoxic ISG induction, intracellular cholesterol distribution appeared critical to enhance hypoxic expression of chemokine ISGs. Importantly, hypoxia further boosted chemokine ISG expression in monocytes upon infection with severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2). Mechanistically, hypoxia sensitized toll-like receptor 4 (TLR4) signaling to activation by SARS-CoV-2 spike protein, which emerged as a major signaling hub to enhance chemokine ISG induction following SARS-CoV-2 infection of hypoxic monocytes. These data depict a hypoxia-regulated immunometabolic mechanism with implications for the development of systemic inflammatory responses in severe cases of coronavirus disease-2019 (COVID-19).

The circular RNA landscape in multiple sclerosis: Disease-specific associated variants and exon methylation shape circular RNA expression profile

BACKGROUND

Circular RNAs (circRNAs) are a class of non-coding RNAs increasingly emerging as crucial actors in the pathogenesis of human diseases, including autoimmune and neurological disorders as multiple sclerosis (MS). Despite several efforts, the mechanisms regulating circRNAs expression are still largely unknown and the circRNA profile and regulation in MS-relevant cell models has not been completely investigated. In this work, we aimed at exploring the global landscape of circRNA expression in MS patients, also evaluating a possible correlation with their genetic and epigenetic background.

METHODS

We performed RNA-seq experiments on circRNA-enriched samples, derived from peripheral blood mononuclear cells (PBMCs) of 10 MS patients and 10 matched controls and performed differential circRNA expression. The genetic background was evaluated using array genotyping, and an expression quantitative trait loci (eQTL) analysis was carried out.

RESULTS

Expression analysis revealed 166 differentially expressed circRNAs in MS patients, 125 of which are downregulated. One of the top dysregulated circRNAs, hsa_circ_0007990, derives from the PGAP3 gene, encoding a protein relevant for the control of autoimmune responses. The downregulation of this circRNA was confirmed in two independent replication cohorts, suggesting its implementation as a possible RNA-based biomarker. The eQTL analysis evidenced a significant association between 89 MS-associated loci and the expression of at least one circRNA, suggesting that MS-associated variants could impact on disease pathogenesis by altering circRNA profiles. Finally, we found a significant correlation between exon methylation and circRNA expression levels, supporting the hypothesis that epigenetic features may play an important role in the definition of the cell circRNA pool.

CONCLUSION

We described the circRNA expression profile of PBMCs in MS patients, suggesting that MS-associated variants may tune the expression levels of circRNAs acting as "circ-QTLs", and proposing a role for exon-based DNA methylation in regulating circRNA expression.

Detailed stratified GWAS analysis for severe COVID-19 in four European populations

Given the highly variable clinical phenotype of Coronavirus disease 2019 (COVID-19), a deeper analysis of the host genetic contribution to severe COVID-19 is important to improve our understanding of underlying disease mechanisms. Here, we describe an extended genome-wide association meta-analysis of a well-characterized cohort of 3255 COVID-19 patients with respiratory failure and 12 488 population controls from Italy, Spain, Norway and Germany/Austria, including stratified analyses based on age, sex and disease severity, as well as targeted analyses of chromosome Y haplotypes, the human leukocyte antigen region and the SARS-CoV-2 peptidome. By inversion imputation, we traced a reported association at 17q21.31 to a ~0.9-Mb inversion polymorphism that creates two highly differentiated haplotypes and characterized the potential effects of the inversion in detail. Our data, together with the 5th release of summary statistics from the COVID-19 Host Genetics Initiative including non-Caucasian individuals, also identified a new locus at 19q13.33, including NAPSA, a gene which is expressed primarily in alveolar cells responsible for gas exchange in the lung.

MicroRNA-200c Attenuates the Tumor-Infiltrating Capacity of Macrophages

Simple Summary

The tumor microenvironment determines the prognosis and outcome for cancer patients. Herein, tumor-associated macrophages are not only highly abundant, but also play a crucial role in shaping a tumor-supporting microenvironment. Both their recruitment to the tumor as well as their functional polarization toward a pro-tumorigenic phenotype are mediated by tumor-derived factors including microRNAs. However, the impact of most microRNAs on the tumor cell-macrophage crosstalk remains to be elucidated. Thus, we reached out to investigate the role of hsa-miR-200c-3p (miR-200c) in tumor cell–macrophage interactions, as it was shown to be differentially expressed during cancer progression and metastasis. miR-200c was highly expressed in MCF7 breast tumor cells compared to macrophages. Furthermore, we identified a CD36-dependent uptake of miR-200c, derived from apoptotic tumor cells, into macrophages. In macrophages, elevated miR-200c levels reduced the expression of numerous migration-associated mRNAs, consequently reducing the capacity of macrophages to infiltrate into tumor spheroids. Finally, a distinct signature of miR-200c-repressed, predicted targets was identified, which strongly correlated with tumor infiltration. Targeting the miR-200c transfer from dying tumor cells to macrophages might therefore provide the opportunity to specifically modulate tumor-associated macrophage recruitment.

Abstract

Macrophages constitute a major part of the tumor-infiltrating immune cells. Within the tumor microenvironment, they acquire an alternatively activated, tumor-supporting phenotype. Factors released by tumor cells are crucial for the recruitment of tumor-associated macrophages. In the present project, we aimed to understand the role of hsa-miR-200c-3p (miR-200c) in the interplay between tumor cells and macrophages. To this end, we employed a coculture system of MCF7 breast tumor cells and primary human macrophages and observed the transfer of miR-200c from apoptotic tumor cells to macrophages, which required intact CD36 receptor in macrophages. We further comprehensively determined miR-200c targets in macrophages by mRNA-sequencing and identified numerous migration-associated mRNAs to be downregulated by miR-200c. Consequently, miR-200c attenuated macrophage infiltration into 3-dimensional tumor spheroids. miR-200c-mediated reduction in infiltration further correlated with a miR-200c migration signature comprised of the four miR-200c-repressed, predicted targets PPM1F, RAB11FIB2, RDX, and MSN.

DNA Methylation Signature in Monozygotic Twins Discordant for Psoriatic Disease

Background: Psoriatic disease is a multifactorial inflammatory condition spanning from skin and nail psoriasis (Pso) to spine and joint involvement characterizing psoriatic arthritis (PsA). Monozygotic twins provide a model to investigate genetic, early life environmental exposure and stochastic influences to complex diseases, mainly mediated by epigenetics.

Methods: We performed a genome-wide DNA methylation study on whole blood of monozygotic twins from 7 pairs discordant for Pso/PsA using the Infinium Methylation EPIC array (Illumina). MeDiP—qPCR was used to confirm specific signals. Data were replicated in an independent cohort of seven patients with Pso/PsA and 3 healthy controls. Transcriptomic profiling was performed by RNAsequence on the same 7 monozygotic twin pairs.

Results: We identified 2,564 differentially methylated positions between psoriatic disease and controls, corresponding to 1,703 genes, 59% within gene bodies. There were 19 regions with at least two DMPs within 1 kb of distance and significant within-pair Δβ-values (p < 0.005), among them SNX25, BRG1 and SMAD3 genes, all involved in TGF-β signaling pathway, were identified. Co-expression analyses on transcriptome data identified IL-6/JAK/STAT3 and TNF-α pathways as important signaling axes involved in the disease, and they also suggested an altered glucose metabolism in patients’ immune cells, characteristic of pro-inflammatory T lymphocytes.

Conclusion: The study suggests the presence of an epigenetic signature in affected individuals, pointing to genes involved in immunological and inflammatory responses. This result is also supported by transcriptome data, that altogether suggest a higher activation state of the immune system, that could promote the disease status.

X Chromosome Contribution to the Genetic Architecture of Primary Biliary Cholangitis

BACKGROUND & AIMS

Genome-wide association studies in primary biliary cholangitis (PBC) have failed to find X chromosome (chrX) variants associated with the disease. Here, we specifically explore the chrX contribution to PBC, a sexually dimorphic complex autoimmune disease.

METHODS

We performed a chrX-wide association study, including genotype data from 5 genome-wide association studies (from Italy, United Kingdom, Canada, China, and Japan; 5244 case patients and 11,875 control individuals).

RESULTS

Single-marker association analyses found approximately 100 loci displaying P < 5 × 10-4, with the most significant being a signal within the OTUD5 gene (rs3027490; P = 4.80 × 10-6; odds ratio [OR], 1.39; 95% confidence interval [CI], 1.028-1.88; Japanese cohort). Although the transethnic meta-analysis evidenced only a suggestive signal (rs2239452, mapping within the PIM2 gene; OR, 1.17; 95% CI, 1.09-1.26; P = 9.93 × 10-8), the population-specific meta-analysis showed a genome-wide significant locus in East Asian individuals pointing to the same region (rs7059064, mapping within the GRIPAP1 gene; P = 6.2 × 10-9; OR, 1.33; 95% CI, 1.21-1.46). Indeed, rs7059064 tags a unique linkage disequilibrium block including 7 genes: TIMM17B, PQBP1, PIM2, SLC35A2, OTUD5, KCND1, and GRIPAP1, as well as a superenhancer (GH0XJ048933 within OTUD5) targeting all these genes. GH0XJ048933 is also predicted to target FOXP3, the main T-regulatory cell lineage specification factor. Consistently, OTUD5 and FOXP3 RNA levels were up-regulated in PBC case patients (1.75- and 1.64-fold, respectively).

CONCLUSIONS

This work represents the first comprehensive study, to our knowledge, of the chrX contribution to the genetics of an autoimmune liver disease and shows a novel PBC-related genome-wide significant locus.

Mutation profile and immunoscore signature in thymic carcinomas: An exploratory study and review of the literature

Background

Significant efforts have been made to investigate the molecular pathways involved in thymic carcinogenesis. However, genetic findings have still not impacted clinical practice. The aim of this exploratory trial was to evaluate the immunoscore and molecular profile of a series of thymic carcinomas (TCs), correlating this data with clinical outcome.

Methods

Formalin‐fixed, paraffin‐embedded (FFPE) TC tissues were retrieved from our center archive. The immunoscore was evaluated according to Angell and Gallon. DNA was extracted from FFPE tumor samples and, when available, from adjacent histologically normal tissues. Next‐generation sequencing (NGS) was performed targeting hotspot regions of 50 oncogenes and tumor suppressor genes.

Results

A series of 15 TCs were analyzed. After a median follow‐up of 82.4 months, the median overall survival was 104.7 months. The immunoscore was >2 in 5/15 patients (33%). Among the investigated genes, absence of mutations was observed in 5/15 patients (33%), whereas three variants in 1/15 (6%) patient, two variants in 4/15 (26%) patients, and one variant in 5/15 patients (33%) were found. The most recurrently mutated genes were FGFR3 (five mutations) and CDKN2A (three mutations, two of which were nonsense). Patients with CDKN2A loss showed a statistically significantly worse survival (P = 0.0013), whereas patients with FGFR3 mutations showed a statistically significantly better survival (P = 0.048).

Conclusions

This study adds data to the few existing reports on the mutational landscape of TCs, providing the first comprehensive analysis to date. Here, we confirm the low rate of mutations in TCs and suggest FGFR3 and CDKN2A mutations as intriguing potential therapeutic targets.

Genomewide Association Study of Severe Covid-19 with Respiratory Failure

BACKGROUND

There is considerable variation in disease behavior among patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (Covid-19). Genomewide association analysis may allow for the identification of potential genetic factors involved in the development of Covid-19.

METHODS

We conducted a genomewide association study involving 1980 patients with Covid-19 and severe disease (defined as respiratory failure) at seven hospitals in the Italian and Spanish epicenters of the SARS-CoV-2 pandemic in Europe. After quality control and the exclusion of population outliers, 835 patients and 1255 control participants from Italy and 775 patients and 950 control participants from Spain were included in the final analysis. In total, we analyzed 8,582,968 single-nucleotide polymorphisms and conducted a meta-analysis of the two case-control panels.

RESULTS

We detected cross-replicating associations with rs11385942 at locus 3p21.31 and with rs657152 at locus 9q34.2, which were significant at the genomewide level (P<5×10-8) in the meta-analysis of the two case-control panels (odds ratio, 1.77; 95% confidence interval [CI], 1.48 to 2.11; P = 1.15×10-10; and odds ratio, 1.32; 95% CI, 1.20 to 1.47; P = 4.95×10-8, respectively). At locus 3p21.31, the association signal spanned the genes SLC6A20, LZTFL1, CCR9, FYCO1, CXCR6 and XCR1. The association signal at locus 9q34.2 coincided with the ABO blood group locus; in this cohort, a blood-group-specific analysis showed a higher risk in blood group A than in other blood groups (odds ratio, 1.45; 95% CI, 1.20 to 1.75; P = 1.48×10-4) and a protective effect in blood group O as compared with other blood groups (odds ratio, 0.65; 95% CI, 0.53 to 0.79; P = 1.06×10-5).

CONCLUSIONS

We identified a 3p21.31 gene cluster as a genetic susceptibility locus in patients with Covid-19 with respiratory failure and confirmed a potential involvement of the ABO blood-group system. (Funded by Stein Erik Hagen and others.).

Not only cancer: the long non-coding RNA MALAT1 affects the repertoire of alternatively spliced transcripts and circular RNAs in multiple sclerosis

Long non-coding RNAs (lncRNAs) are post-transcriptional and epigenetic regulators, whose implication in neurodegenerative and autoimmune diseases remains poorly understood. We analyzed publicly available microarray data sets to identify dysregulated lncRNAs in multiple sclerosis (MS), a neuroinflammatory autoimmune disease. We found a consistent upregulation in MS of the lncRNA MALAT1 (2.7-fold increase; meta-analysis, P = 1.3 × 10-8; 190 cases, 182 controls), known to regulate alternative splicing (AS). We confirmed MALAT1 upregulation in two independent MS cohorts (1.5-fold increase; P < 0.01; 59 cases, 50 controls). We hence performed MALAT1 overexpression/knockdown in cell lines, demonstrating that its modulation impacts on endogenous expression of splicing factors (HNRNPF and HNRNPH1) and on AS of MS-associated genes (IL7R and SP140). Minigene-based splicing assays upon MALAT1 modulation recapitulated IL7R and SP140 isoform unbalances observed in patients. RNA-sequencing of MALAT1-knockdown Jurkat cells further highlighted MALAT1 role in splicing (approximately 1100 significantly-modulated AS events) and revealed its contribution to backsplicing (approximately 50 differentially expressed circular RNAs). Our study proposes a possible novel role for MALAT1 dysregulation and the consequent AS alteration in MS pathogenesis, based on anomalous splicing/backsplicing profiles of MS-relevant genes.

Genetic Association and Altered Gene Expression of CYBB in Multiple Sclerosis Patients

Multiple sclerosis (MS) is a chronic neurological disorder characterized by inflammation, demyelination, and axonal damage. Increased levels of reactive oxygen species (ROS), produced by macrophages and leading to oxidative stress, have been implicated as mediators of demyelination and axonal injury in both MS and experimental autoimmune encephalomyelitis, the murine model of the disease. On the other hand, reduced ROS levels can increase susceptibility to autoimmunity. In this work, we screened for association with MS 11 single nucleotide polymorphisms (SNPs) and two microsatellite markers in the five genes (NCF1, NCF2, NCF4, CYBA, and CYBB) of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX2) system, the enzymatic pathway producing ROS in the brain and neural tissues, in 347 Finnish patients with MS and 714 unaffected family members. This analysis showed suggestive association signals for NCF1 and CYBB (lowest p = 0.038 and p = 0.013, respectively). Functional relevance for disease predisposition was further supported for the CYBB gene, by microarray analysis in CD4^+/− mononuclear cells of 21 individuals from five Finnish multiplex MS families, as well as by real-time RT-PCRs performed on RNA extracted from peripheral blood mononuclear cells of an Italian replication cohort of 21 MS cases and 21 controls. Our results showed a sex-specific differential expression of CYBB, suggesting that this gene, and more in general the NOX2 system, deserve to be further investigated for their possible role in MS.

Interpreting Non-coding Genetic Variation in Multiple Sclerosis Genome-Wide Associated Regions

Multiple sclerosis (MS) is the most common neurological disorder in young adults. Despite extensive studies, only a fraction of MS heritability has been explained, with association studies focusing primarily on protein-coding genes, essentially for the difficulty of interpreting non-coding features. However, non-coding RNAs (ncRNAs) and functional elements, such as super-enhancers (SE), are crucial regulators of many pathways and cellular mechanisms, and they have been implicated in a growing number of diseases. In this work, we searched for possible enrichments in non-coding elements at MS genome-wide associated loci, with the aim to highlight their possible involvement in the susceptibility to the disease. We first reconstructed the linkage disequilibrium (LD) structure of the Italian population using data of 727,478 single-nucleotide polymorphisms (SNPs) from 1,668 healthy individuals. The genomic coordinates of the obtained LD blocks were intersected with those of the top hits identified in previously published MS genome-wide association studies (GWAS). By a bootstrapping approach, we hence demonstrated a striking enrichment of non-coding elements, especially of circular RNAs (circRNAs) mapping in the 73 LD blocks harboring MS-associated SNPs. In particular, we found a total of 482 circRNAs (annotated in publicly available databases) vs. a mean of 194 ± 65 in the random sets of LD blocks, using 1,000 iterations. As a proof of concept of a possible functional relevance of this observation, we experimentally verified that the expression levels of a circRNA derived from an MS-associated locus, i.e., hsa_circ_0043813 from the STAT3 gene, can be modulated by the three genotypes at the disease-associated SNP. Finally, by evaluating RNA-seq data of two cell lines, SH-SY5Y and Jurkat cells, representing tissues relevant for MS, we identified 18 (two novel) circRNAs derived from MS-associated genes. In conclusion, this work showed for the first time that MS-GWAS top hits map in LD blocks enriched in circRNAs, suggesting circRNAs as possible novel contributors to the disease pathogenesis.

Advantages of second-generation long-acting injectable anti-psychotics: Focus on hospital admission rates in southeast Tuscany

Introduction

Several studies suggested that second-generation long-acting injectable anti-psychotics (SGA-LAIs) might be effective on preventing relapse and admission/readmission rates among patients affected by schizophrenic and bipolar disorders. Moreover, studies highlighted that SGA-LAIs may reduce costs and healthcare resource utilization (HRU) among community psychiatric settings.

Objectives

The objective of the present study was to evaluate whether the increased use of SGA-LAIs among community psychiatric services in southern Tuscany was related to:

– reduced costs and HRU;

– reduced hospital admission/readmission.

Methods

Data consisted of both regional registry and data prospectively collected at admission and/or follow up assessments. Patients included were: patients affected by schizophrenia/schizoaffective or bipolar disorders, treated with SGA-LAIs.

Results

The increased use of SGA-LAIs was related to a significant reduction of admission and/or readmission rates, as long as a significant reduction in costs and HRU among the community services included in the study.

Conclusions

The present findings suggest that SGA-LAIs might have a positive cost/effectiveness profile and could reduce hospitalizations, costs and HRU among a community sample. This could be related to a better tolerability of SGA-LAIs compared to FGA-LAIs, and less adverse effects. More studies on community samples should focus on the cost/effectiveness profile of SGA-LAIs.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

The Characterization of GSDMB Splicing and Backsplicing Profiles Identifies Novel Isoforms and a Circular RNA That Are Dysregulated in Multiple Sclerosis

Abnormalities in alternative splicing (AS) are emerging as recurrent features in autoimmune diseases (AIDs). In particular, a growing body of evidence suggests the existence of a pathogenic association between a generalized defect in splicing regulatory genes and multiple sclerosis (MS). Moreover, several studies have documented an unbalance in alternatively-spliced isoforms in MS patients possibly contributing to the disease etiology. In this work, using a combination of PCR-based techniques (reverse-transcription (RT)-PCR, fluorescent-competitive, real-time, and digital RT-PCR assays), we investigated the alternatively-spliced gene encoding Gasdermin B, GSDMB, which was repeatedly associated with susceptibility to asthma and AIDs. The in-depth characterization of GSDMB AS and backsplicing profiles led us to the identification of an exonic circular RNA (ecircRNA) as well as of novel GSDMB in-frame and out-of-frame isoforms. The non-productive splicing variants were shown to be downregulated by the nonsense-mediated mRNA decay (NMD) in human cell lines, suggesting that GSDMB levels are significantly modulated by NMD. Importantly, both AS isoforms and the identified ecircRNA were significantly dysregulated in peripheral blood mononuclear cells of relapsing-remitting MS patients compared to controls, further supporting the notion that aberrant RNA metabolism is a characteristic feature of the disease.

miR-634 is a Pol III-dependent intronic microRNA regulating alternative-polyadenylated isoforms of its host gene PRKCA

BACKGROUND

The protein kinase C alpha (PRKCA) gene, coding for a Th17-cell-selective kinase, shows a complex splicing pattern, with at least 2 stable alternative transcripts characterized by an alternative upstream polyadenylation site. Polymorphisms in this gene were associated with several conditions, including multiple sclerosis, asthma, schizophrenia, and cancer. The presence of a microRNA (miRNA), i.e. miR-634, within intron 15 of the PRKCA gene, suggests the intriguing possibility that this miRNA might play a role in the susceptibility to these pathologies.

METHODS

Here, we characterized miR-634 expression profile and searched for its putative targets using a combination of RT-PCR and gene reporter assays.

RESULTS

The quantitative analysis of PRKCA and miR-634 transcripts in a panel of human tissues and cell lines revealed discordant expression profiles, suggesting the presence of an independent miR-634 promoter and/or a possible direct role of miR-634 in modulating PRKCA expression. Functional studies demonstrated the existence of a miRNA-specific promoter, which was shown to be Pol-III-dependent. Furthermore, transfection experiments showed that miR-634 is able to target its host gene by specifically down-regulating the shorter alternative-polyadenylated isoforms.

CONCLUSIONS

MiR-634 is a Pol III-dependent intronic miRNA, which could target its host gene through a "first-order" negative feedback.

GENERAL SIGNIFICANCE

MiR-634 is one of the few characterized examples of Pol-III-dependent intronic miRNAs. Its independent transcription from the host gene suggests caution in using expression profiles of host genes as proxies for the expression of the corresponding intronic miRNAs.

Meta-Analysis of Multiple Sclerosis Microarray Data Reveals Dysregulation in RNA Splicing Regulatory Genes

Abnormalities in RNA metabolism and alternative splicing (AS) are emerging as important players in complex disease phenotypes. In particular, accumulating evidence suggests the existence of pathogenic links between multiple sclerosis (MS) and altered AS, including functional studies showing that an imbalance in alternatively-spliced isoforms may contribute to disease etiology. Here, we tested whether the altered expression of AS-related genes represents a MS-specific signature. A comprehensive comparative analysis of gene expression profiles of publicly-available microarray datasets (190 MS cases, 182 controls), followed by gene-ontology enrichment analysis, highlighted a significant enrichment for differentially-expressed genes involved in RNA metabolism/AS. In detail, a total of 17 genes were found to be differentially expressed in MS in multiple datasets, with CELF1 being dysregulated in five out of seven studies. We confirmed CELF1 downregulation in MS (p = 0.0015) by real-time RT-PCRs on RNA extracted from blood cells of 30 cases and 30 controls. As a proof of concept, we experimentally verified the unbalance in alternatively-spliced isoforms in MS of the NFAT5 gene, a putative CELF1 target. In conclusion, for the first time we provide evidence of a consistent dysregulation of splicing-related genes in MS and we discuss its possible implications in modulating specific AS events in MS susceptibility genes.

Mutagenicity of dichlorvos and other structurally related pesticides in Salmonella and Streptomyces

The following pesticides: azinphosmethyl, diallate, dichlorvos, EPTC, fenchlorphos, mevinphos, monocrotophos, noruron, parathionmethyl, triallate, trichlorphon and vegadex were tested for the ability to induce his+ revertants in four histidines requiring strains of Salmonella typhimurium--TAI 535(missense), TAI 536, TAI 537 and TAI 538 (frame-shift)- and resistance to low levels of streptomycin in Streptomyces coelicolor. Dichlorvos, which is a phosphoric ester with a dichlorovinyl group as side chain, and trichlorphon, which is known for its spontaneous conversion in dichlorvos, are both mutagenic in Salmonella (strain TAI535) and Streptomyces. Five organophosphorus pesticides similar to dichlorvos but devoid of the vinyl group are not mutagenic. Three carbamates, diallate, triallate and vegadex, which contain a chloroallyl group similar to the vinyl group of dichlorvos are mutagenic in Streptomyes; triallate and vegadex are powerful mutagens also in Salmonella (strain TAI535); two other carbamates devoid of the chlorinated group are not mutagenic. The results suggest that the presence of a vinyl chloride or allyl chloride group in the molecule of these pesticides is responsible for the ability to induce point mutations in Salmonella and Streptomyces.

Microbiological mutagenicity studies of pesticides in vitro

14 pesticides were tested as pure compounds for the induction of point mutations in four strains of Salmonella typhimurium--TA1535, TA1536, TA1537 and TA1538--in the presence and in the absence of rat-liver microsomal fractions and for the induction of resistance to low concentrations of streptomycin in the filamentous bacterium, Streptomyces coelicolor. The technique used was essentially the so-called "spot test". The pesticides investigated were: aminotriazole, Benomyl, Captafol, Captan, Dichlorvos, Dalapon-Na, Dinobuton, Dodine, Ioxynil, Mecoprop, Neburon, Picloram, Triallate and Trichlorphon. In Salmonella, Captan and Triallate were mutagenic on the TA1535 strain; Dichlorvos and Trichlorphon were negative in the spot test but mutagenic after incubation in liquid cultures of strain TA1535. By using the S. coelicolor forward-mutation test, aminotriazole, Dichlorvos, Picloram, Trichlorphon and Triallate were mutagenic with the "spot test" technique; Captan showed a weak mutagenic activity with a "plate-incorporated" technique.