Search bioRxiv⌕ Search

Biology subjects

Ferrari, R.

Publications and source records attributed to Ferrari, R..

12 recordsLinked to original sources

Human ASPDH is a 2-aminomuconate reductase that produces L-2-aminohex-3-enedioic acid in tryptophan catabolism

Most tryptophan catabolism in animals occurs through the kynurenine pathway, which generates the essential NAD cofactor and multiple bioactive metabolites. Knowledge of this pathway in eukaryotes ends at the unstable intermediate 2-aminomuconate (2-AM). Here, by leveraging evolutionary information from more than 5,000 eukaryotes, we identify two distinct genes acting downstream of 2-AM in fungi and metazoa. The fungal gene is homologous to bacterial 2-AM deaminase, whereas the metazoan gene is homologous to aspartate dehydrogenase (ASPDH), which in prokaryotes catalyses the first reaction of NAD biosynthesis. Biochemical and structural analyses show that human ASPDH has evolved an unprecedented function as an NAD(P)H-dependent 2-AM reductase (AMR) in tryptophan catabolism. The reaction forms L-2-aminohex-3-enedioic acid, an unsaturated -amino acid absent from current biological databases. Isotope-labeling NMR experiments and structural modelling support a mechanism in which hydride transfer is coupled to double-bond rearrangement of the conjugated system. These findings reveal a previously unknown metazoan branch of the kynurenine pathway, expand the repertoire of endogenous amino acids, and illustrate how comparative genomics can uncover hidden reactions in human metabolism.

biochemistry↗

PARP1 Regulates 3D Structure and Function of Super-Enhancers and Hormone-Control Regions in Breast Cancer Cells

Poly (ADP-ribose) polymerase 1 (PARP1) has been linked to various genomic pathways and in the maintenance of genomic stability. PARP1 has also been postulated to regulate cis-regulatory elements, but the mechanisms remain largely unknown. Here, we employed genomic approaches to show how PARP1 occupies Super-Enhancers (SEs) of luminal A T47D breast cancer cells and how some PARP1 is dynamically relodged by progesterone at hormone-control regions (HCRs). Disruption of PARP1 causes transcriptome reprogramming, altering the expression of both SE-associated and HCRs-regulated genes. This is achieved through a dual coordinated action in the establishment of long-range and intra-TADs chromatin loops, which are lost upon PARP1 ablation, but enforced by its catalytic inhibition. We show that PARP1 also plays a role in regulation of chromatin compartments. Our results reveal PARP1, as a new chromatin looper and compartments organizer controlling SEs and HCRs genes linked to cell identity and hormonal response in breast cancer cells via 3D genome organization. Highlights (Separate document)O_LIPARP1 occupies cell specific super-enhancers and hormone-control regions. C_LIO_LILoss of PARP1 alters the cell identity and progestin-induced gene expression signature. C_LIO_LIGene expression changes upon PARP1 loss relay on altered 3D chromatin looping and compartments. C_LI eTOC blurbWe have discovered that the nuclear repair protein and cancer drug target; PARP1 is preferentially bound at super-enhancers. The binding of PARP1 is essential for the underlying, cell specific gene expression program and the 3D structure of the chromatin surrounding the super-enhancer regions. Graphical abstractSeparate document O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=198 SRC="FIGDIR/small/668155v1_ufig1.gif" ALT="Figure 1"> View larger version (81K): org.highwire.dtl.DTLVardef@1da9027org.highwire.dtl.DTLVardef@2e1966org.highwire.dtl.DTLVardef@8582eaorg.highwire.dtl.DTLVardef@155e77b_HPS_FORMAT_FIGEXP M_FIG C_FIG

genomics↗

The Hippo kinase LATS1 controls CTCF chromatin occupancy and the hormonal response of three-dimensionally grown breast cancer cells

The cancer epigenome has been studied in cells cultured in 2D monolayers on plastic surfaces, but recent studies highlight the impact of the extracellular matrix (ECM) and the 3D environment on multiple cellular functions. Here, we report the physical, biochemical and genomic differences between T47D breast cancer cells cultured in 2D monolayer and as 3D spheroids in Matrigel. Cells within 3D spheroids exhibit a rounder nucleus with less accessible, more compacted chromatin, and altered expression of over 2,000 genes, the majority of which become repressed. Hi-C analysis reveals that cells grown in 3D exhibit enrichment in regions belonging to the B compartment, decrease on chromatin bound CTCF and increased fusion of Topologically Associating Domains (TADs). Upregulation of the Hippo pathway in 3D spheroids results in the activation of the LATS1 kinase, which promotes phosphorylation and displacement of CTCF from DNA, likely responsible for the observed TAD fusions. Cells grown in 3D exhibit higher progesterone receptor (PR) binding to chromatin, leading to an increase in the number hormone-regulated genes. This effect is in part mediated by the LATS1 activation, which favors cytoplasmic retention of YAP and CTCF removal.

genomics↗

A progesterone derivative linked to a stable phospholipid activates breast cancer cell response without leaving the cell membrane

In hormone-responsive breast cancer cells, progesterone (P4) has been shown to act via its nuclear receptor (PR), a ligand-activated transcription factor. A small fraction of PR is palmitoylated and anchored to the cell membrane (mbPR) forming a complex with estrogen receptor alpha (ER). Upon hormone exposure, either directly or via interaction with ER mbPR activates the SRC/RAS/ERK kinase pathway leading to phosphorylation of PR by ERK. Kinase activation is essential for P4 gene regulation, as the ERK and MSK1 kinases are recruited by the PR to its genomic binding sites and trigger chromatin remodeling. An interesting open question is whether activation of mbPR can result in gene regulation in the absence of ligand binding to intracellular PR. This matter has been investigated in the past using P4 attached to serum albumin, but the attachment is leaky and albumin can be endocytosed and degraded, liberating P4. Here we propose a more stringent approach to address this issue by ensuring attachment of P4 to the cell membrane via covalent binding to a stable phospholipid. This strategy identifies the actions of P4 independent of hormone binding to intracellular PR. We found that a membrane-attached progestin can activate mbPR, the ERK signalling pathway leading to PR phosphorylation, initial gene regulation and entry into the cell cycle, in the absence of detectable intracellular progestin.

genomics↗

The GUN mutants: new weapons to unravel ascospore germination regulation in the model fungus Podospora anserina

In Podospora anserina as in many other ascomycetes, ascospore germination is a regulated process that requires breaking of dormancy. Despite its importance in survival and dispersal, ascospore germination in filamentous fungi has been poorly investigated and little is known about its regulation and genetic control. We have designed a positive genetic screen that led to the isolation of mutants showing uncontrolled germination, the GUN mutants. In this paper, we report on the characterization of GUN1SG. We show that GUN1SG is mutated in Pa_6_1340, the ortholog of Magnaporthe oryzae Pth2, which encodes a Carnitine-acetyltransferase (CAT) involved in the shuttling of acetyl-CoA between peroxisomes and mitochondria and which is required for appressorium-development. Bioinformatic analysis revealed that the mutated residue (I441) is highly conserved among the Fungi, and that the mutation has a deleterious impact on the protein function. We show that GUN1 is essential for ascospore germination and that the protein is localized both in mitochondria and in peroxisomes. Finally, epistasis studies allowed us to place GUN1 upstream of the PaMpk2 MAPK pathway and the PaNox2/PaPls1 complex in the regulation of ascospore germination. The identification of GUN1, the ortholog of Pth2, in ascospore germination, strengthens the idea of a common genetic regulation governing both appressorium development and melanized ascospore germination. In addition, we characterize the second CAT encoded in P. anserina genome, Pa_3_7660/GUP1, and we show that the function of both CATs is conserved in P. anserina.

genetics↗

The DYRK1A protein kinase regulates ribosome mass and translation rates through transcriptional control of ribosomal protein genes expression

Ribosomal proteins (RPs) are evolutionary conserved proteins that are essential for protein translation. RP expression must be tightly regulated to ensure the appropriate assembly of ribosomes and to respond to the growth demands of cells. The elements regulating the transcription of RP genes (RPGs) have been characterized in yeast and Drosophila, yet how cells regulate the production of RPs in mammals is less well understood. Here, we show that a subset of RPG promoters is characterized by the presence of the palindromic TCTCGCGAGA motif and marked by the recruitment of the protein kinase DYRK1A. The presence of DYRK1A at these promoters is associated with enhanced binding of the TATA-binding protein, TBP, and it is negatively correlated with the binding of the GABP transcription factor, establishing at least two clusters of RPGs that could be coordinately regulated. However, DYRK1A silencing leads to a global reduction of RPGs, mRNA pointing at DYRK1A activities beyond those dependent on its chromatin association. Significantly, cells in which DYRK1A is depleted have reduced RP levels, fewer ribosomes, reduced global protein synthesis and smaller size. We therefore propose a novel role for DYRK1A in coordinating the expression of genes encoding RPs, thereby controlling cell growth in mammals.

molecular biology↗

Common variation at the LRRK2 locus is associated with survival in the primary tauopathy progressive supranuclear palsy

The genetic basis of variation in the rate of disease progression of primary tauopathies has not been determined. In two independent progressive supranuclear palsy cohorts, we show that common variation at the LRRK2 locus determines survival from motor symptom onset to death, possibly through regulation of gene expression. This links together genetic risk in alpha-synuclein and tau disorders, and suggests that modulation of proteostasis and neuro-inflammation by LRRK2 inhibitors may have a therapeutic role across disorders.

genetics↗

PINOT: An Intuitive Resource for Integrating Protein-Protein Interactions

The past decade has seen the rise of omics data, for the understanding of biological systems in health and disease. This wealth of data includes protein-protein interaction (PPI) derived from both low and high-throughput assays, which is curated into multiple databases that capture the extent of available information from the peer-reviewed literature. Although these curation efforts are extremely useful, reliably downloading and integrating PPI data from the variety of available repositories is challenging and time consuming.\n\nWe here present a novel user-friendly web-resource called PINOT (Protein Interaction Network Online Tool; available at http://www.reading.ac.uk/bioinf/PINOT/PINOT_form.html) to optimise the collection and processing of PPI data from the IMEx consortium associated repositories (members and observers) and from WormBase for constructing, respectively, human and C. elegans PPI networks.\n\nUsers submit a query containing a list of proteins of interest for which PINOT will mine PPIs. PPI data is downloaded, merged, quality checked, and confidence scored based on the number of distinct methods and publications in which each interaction has been reported. Examples of PINOT applications are provided to highlight the performance, the ease of use and the potential applications of this tool.\n\nPINOT is a tool that allows users to survey the literature, extracting PPI data for a list of proteins of interest. The comparison with analogous tools showed that PINOT was able to extract similar numbers of PPIs while incorporating a set of innovative features. PINOT processes both small and large queries, it downloads PPIs live through PSICQUIC and it applies quality control filters on the downloaded PPI annotations (i.e. removing the need of manual inspection by the user). PINOT provides the user with information on detection methods and publication history for each of the downloaded interaction data entry and provides results in a table format that can be easily further customised and/or directly uploaded in a network visualization software.

bioinformatics↗

Integration of eQTL and Parkinson’s disease GWAS data implicates 11 disease genes

Substantial genome-wide association study (GWAS) work in Parkinsons disease (PD) has led to an increasing number of loci shown reliably and robustly to be associated with the increased risk of the disease. Prioritising causative genes and pathways from these studies has proven problematic. Here, we present a comprehensive analysis of PD GWAS data with expression and methylation quantitative trait loci (eQTL/mQTL) using Colocalisation analysis (Coloc) and transcriptome-wide association analysis (TWAS) to uncover putative gene expression and splicing mechanisms driving PD GWAS signals. Candidate genes were further characterised by determining cell-type specificity, weighted gene co-expression (WGNCA) and protein-protein interaction (PPI) networks.\n\nGene-level analysis of expression revealed 5 genes (WDR6, CD38, GPNMB, RAB29, TMEM163) that replicated using both Coloc and TWAS analyses in both GTEx and Braineac expression datasets. A further 6 genes (ZRANB3, PCGF3, NEK1, NUPL2, GALC, CTSB) showed evidence of disease-associated splicing effects. Cell-type specificity analysis revealed that gene expression was overall more prevalent in glial cell-types compared to neurons. The WGNCA analysis showed that NUPL2 is a key gene in 3 modules implicated in catabolic processes related with protein ubiquitination (protein ubiquitination (p=7.47e-10) and ubiquitin-dependent protein catabolic process (p = 2.57e-17) in nucleus accumbens, caudate and putamen, while TMEM163 and ZRANB3 were both important in modules indicating regulation of signalling (p=1.33e-65] and cell communication (p=7.55e-35) in the frontal cortex and caudate respectively. PPI analysis and simulations using random networks demonstrated that the candidate genes interact significantly more with known Mendelian PD and parkinsonism proteins than would be expected by chance. The proteins core proteins this network were enriched for regulation of the ERBB receptor tyrosine protein kinase signalling pathways.\n\nTogether, these results point to a number of candidate genes and pathways that are driving the associations observed in PD GWAS studies.

neuroscience↗

TFIIIC dynamically binds Alu elements to control gene expression through chromatin looping

Folding of the mammalian genome is governed by architectural proteins, such as CTCF. TFIIIC, a RNA polymerase III transcription factor, has been identified as an insulator but its role in genome topology is totally unknown. Here, we show that TFIIIC establishes long-range genomic interactions that affect gene expression. Upon serum starvation (SS), TFIIIC occupancy increases at Alu elements (AEs) near promoters of cell cycle-related genes. Bound AEs become H3K18 hyper-acetylated and fold to contact distal pre-loaded CTCF sites near other cell cycle genes. The promoters of these genes also become hyper-acetylated ensuring their basal transcription during SS and their increased expression during serum re-exposure. Ablation of TFIIIC or deletion of the TFIIIC-bound AE that loops to the G2/M cycling F (CCNF) locus affects its expression and nuclear positioning. These results illustrate a novel function of human TFIIIC in changing 3D genome topology through the epigenetic state of AEs.\n\nHighlightsO_LISerum starvation enhances TFIIIC binding to Alu Elements (AEs) near cell cycle genes\nC_LIO_LIBinding of TFIIIC increases H3K18 acetylation over the bound AE\nC_LIO_LITFIIIC-mediated looping to distal genes favors their reactivation upon serum addition\nC_LIO_LILong-range TFIIIC interactions tune cell cycle genes expression through nuclear repositioning\nC_LI\n\nGraphical abstract\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=64 SRC=\"FIGDIR/small/455733_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (22K):\norg.highwire.dtl.DTLVardef@917ee4org.highwire.dtl.DTLVardef@21d0fborg.highwire.dtl.DTLVardef@1f1a17org.highwire.dtl.DTLVardef@1e9df24_HPS_FORMAT_FIGEXP M_FIG C_FIG

genomics↗

Variation at the TRIM11 locus modifies Progressive Supranuclear Palsy phenotype

ObjectiveThe basis for clinical variation related to underlying Progressive Supranuclear Palsy (PSP) pathology is unknown. We performed a genome wide association study (GWAS) to identify genetic determinants of PSP phenotype.\n\nMethodsTwo independent pathological and clinically diagnosed PSP cohorts were genotyped and phenotyped to create Richardsons syndrome (RS) and non-RS groups. We carried out separate logistic regression GWAS to compare RS and non-RS groups and then combined datasets to carry out a whole cohort analysis (RS=367, non-RS=130). We validated our findings in a third cohort by referring to data from 100 deeply phenotyped cases from a recent GWAS. We assessed the expression/co-expression patterns of our identified genes and used our data to carry out gene-based association testing.\n\nResultsOur lead single nucleotide polymorphism (SNP), rs564309, showed an association signal in both cohorts, reaching genome wide significance in our whole cohort analysis - OR 5.5 (3.2-10.0), p-value 1.7x10-9. rs564309 is an intronic variant of the tripartite motif-containing protein 11 (TRIM11) gene, a component of the ubiquitin proteasome system (UPS). In our third cohort, minor allele frequencies of surrogate SNPs in high linkage disequilibrium with rs564309 replicated our findings. Gene based association testing confirmed an association signal at TRIM11. We found that TRIM11 is predominantly expressed neuronally, in the cerebellum and basal ganglia.\n\nInterpretationOur study suggests that the TRIM11 locus is a genetic modifier of PSP phenotype and potentially adds further evidence for the UPS having a key role in tau pathology, therefore representing a target for disease modifying therapies.

neuroscience↗

Immune-related genetic enrichment in frontotemporal dementia

BackgroundConverging evidence suggests that immune-mediated dysfunction plays an important role in the pathogenesis of frontotemporal dementia (FTD). Although genetic studies have shown that immune-associated loci are associated with increased FTD risk, a systematic investigation of genetic overlap between immune-mediated diseases and the spectrum of FTD-related disorders has not been performed.\n\nMethods and findingsUsing large genome-wide association studies (GWAS) (total n = 192,886 cases and controls) and recently developed tools to quantify genetic overlap/pleiotropy, we systematically identified single nucleotide polymorphisms (SNPs) jointly associated with FTD-related disorders namely FTD, corticobasal degeneration (CBD), progressive supranuclear palsy (PSP), and amyotrophic lateral sclerosis (ALS) - and one or more immune-mediated diseases including Crohns disease (CD), ulcerative colitis (UC), rheumatoid arthritis (RA), type 1 diabetes (T1D), celiac disease (CeD), and psoriasis (PSOR). We found up to 270-fold genetic enrichment between FTD and RA and comparable enrichment between FTD and UC, T1D, and CeD. In contrast, we found only modest genetic enrichment between any of the immune-mediated diseases and CBD, PSP or ALS. At a conjunction false discovery rate (FDR) < 0.05, we identified numerous FTD-immune pleiotropic SNPs within the human leukocyte antigen (HLA) region on chromosome 6. By leveraging the immune diseases, we also found novel FTD susceptibility loci within LRRK2 (Leucine Rich Repeat Kinase 2), TBKBP1 (TANK-binding kinase 1 Binding Protein 1), and PGBD5 (PiggyBac Transposable Element Derived 5). Functionally, we found that expression of FTD-immune pleiotropic genes (particularly within the HLA region) is altered in postmortem brain tissue from patients with frontotemporal dementia and is enriched in microglia compared to other central nervous system (CNS) cell types.\n\nConclusionsWe show considerable immune-mediated genetic enrichment specifically in FTD, particularly within the HLA region. Our genetic results suggest that for a subset of patients, immune dysfunction may contribute to risk for FTD. These findings have potential implications for clinical trials targeting immune dysfunction in patients with FTD.

genetics↗