Biology subjects

Andersson, E.

Publications and source records attributed to Andersson, E..

18 recordsLinked to original sources

bioRxiv2026

Vgll3a promotes sexual maturation in male and female Atlantic salmon

The age at which Atlantic salmon reaches sexual maturity shows a strong hereditary component associated with the vgll3a locus. The role of Vgll3 in maturation has remained unknown in vertebrates until recently, when it has been linked to pleiotropic roles in killifish, both delaying male maturation and affecting lifespan by protecting against cancer. As Atlantic salmon has two vgll3 paralogs, where only vgll3a has been associated with sexual maturation, it may provide a suitable model for studying the maturation-specific function of vgll3, as the other paralog may buffer for pleiotropic roles of vgll3. To address this, we used CRISPR/Cas9 to generate fish highly mutated in the vgll3a gene. We monitored their maturation and crossed highly mutated crispants to generate two year-classes of complete loss-of-function. All groups were reared under environmental conditions triggering early maturation in one-year-old males. We found a clear difference in the proportion of sexually maturing or mature fish between the different genotypes: in all experiments significantly fewer vgll3a-/- males entered puberty and reached final maturation compared to vgll3a+/- and vgll3a+/+ males. Furthermore, loss of vgll3a resulted in lower frequencies of maturation also in females. We conclude that Vgll3a stimulates maturation and that its complete removal significantly reduced maturation rates in both sexes in Atlantic salmon. Our findings also identify vgll3a as the causative gene in the locus associated with age at sexual maturity. Together, our findings support a new role for Vgll3 in initiating puberty in vertebrates and identifying salmon as a promising model for functional studies regarding the timing of sexual maturation.

genomics↗

bioRxiv2026

Urban PM2.5 at Realistic Environmental Concentrations Impairs Blood-Brain Barrier Integrity and Enhances LOX-1 Expression in Human Brain Endothelial Cells

IntroductionAmbient air pollution, especially fine particulate matter 2.5 (PM2.5) has emerged as a critical environmental risk factor for cerebrovascular diseases, contributing to an estimated 7.9 million premature deaths annually. PM2.5 induces cellular toxicity and is hypothesized to disrupt the blood-brain barrier (BBB), a pathological hallmark in cerebrovascular diseases such as ischemic stroke. Despite epidemiological evidence linking PM2.5 to increased stroke incidence, its underlying cellular mechanism driving this association is poorly understood. It remains unclear how environmentally relevant pollution concentrations affects brain endothelial function or influence stroke-related biomarkers such as the lectin-like oxLDL receptor 1 (LOX-1). MethodPrimary adult male human brain microvascular endothelial cells (HBMEC) were exposed to PM2.5 (5, 15, 75, or 300 g/m3) collected from an urban environment in southern Sweden, or control. Thereafter, exposed to normoxia (21% O2) or hypoxia (1% O2) and glucose deprivation, followed by reperfusion as a model for ischemic stroke. Cell viability, oxidative stress, inflammation, BBB integrity (claudin-5, ZO-1) and LOX-1 protein expression were assessed. ResultsPM2.5 exposure induced cellular dysfunction, oxidative stress and inflammation starting at 75 g/m3 PM2.5. Notably, decreased claudin-5 and ZO-1 protein levels and increased LOX-1 expression at concentrations as low as 15 g/m3 PM2.5, levels commonly encountered in urban environments globally. The cellular effects of PM2.5 closely resembled those induced by ischemic-like injury. ConclusionThese findings demonstrate dose-dependent detrimental effects of PM2.5 on HBMEC. The results suggest that ambient urban PM2.5 may act as a predisposing factor for cerebrovascular disease onset, by causing endothelial and barrier dysregulation. HighlightsO_LIUrban PM2.5 dose-dependently disrupts BBB integrity in human brain endothelial cells C_LIO_LIPM2.5 induces endothelial dysfunction resembling ischemic-like injury C_LIO_LIUrban PM2.5 exposure upregulates cardiovascular disease biomarker LOX-1 C_LIO_LIA majority of the global population are exposed to BBB-disrupting PM2.5 levels C_LIO_LIVascular endothelial- and BBB dysfunction enhances risk for cerebrovascular disease C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=154 SRC="FIGDIR/small/702473v2_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@42cce6org.highwire.dtl.DTLVardef@19a2ff9org.highwire.dtl.DTLVardef@1c38e7corg.highwire.dtl.DTLVardef@1bfa837_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2025

Hic2 fast-tracks iPS cell generation by suppressing KLF4-dependent epidermal detour

Reprogramming somatic cells to induced pluripotent stem cells (iPSCs) is the most established cellular conversion by exogenous master transcription factors (TFs). A deeper understanding of this yet inefficient process is critical to extending our capability to control cellular identity for medical applications. Here we report 14 genes essential for efficient iPSC generation, but dispensable for self-renewal. Of those, overexpression of Hic2, a transcriptional suppressor highly expressed in PSCs, enhances iPSC generation [~]10-fold. This is achieved through a more direct transition towards pluripotency, bypassing an intermediate state with KLF4-dependent transient epidermal gene expression during iPSC generation. Mechanistically, HIC2 co-occupies these KLF4 targets and directly inhibits their expression. Our work demonstrates that master TFs necessary for cellular conversions can also activate obstructive genes during cellular reprogramming. We propose that identifying transcriptional suppressors against such side effects, like Hic2, can be a powerful strategy to achieve more efficient TF-mediated cell conversions.

developmental biology↗

bioRxiv2024

Generating human parvalbumin interneurons through 3D glia reprogramming

Parvalbumin (PV) interneurons are crucial for synaptic plasticity, and their damage or loss is linked to various neurological disorders. Yet, generating these cells of human source in vitro is challenging, limiting advancements in cell repair and disease modelling. We introduce a novel approach to derive human PV neurons through direct reprogramming of glial precursor cells (GPCs). Using ectopic expression of GABAergic neuronal genes, GPCs efficiently convert into GABAergic interneurons in 3D culture environment within weeks and achieve functional neuronal maturity. Single-nuclei RNA sequencing identified a distinct PV neuronal cluster with high maturity and characteristics of PV chandelier subclass that are equivalent to bona fide human interneurons. Trajectory analysis revealed a distinct glia-to-PV interneuron conversion pathway, involving several new transitory genes, with potential for functional importance for PV derivation. Our data introduces a new strategy for generating human PV interneurons, promising significant implications for future generation of patient-specific PV neurons both in vitro and in vivo. HighlightsO_LIA novel approach to derive human PV interneurons by direct glia reprogramming. C_LIO_LIFirst comprehensive transcriptomic profiling of induced human PV interneurons. C_LIO_LIInduced PV interneurons are of chandelier subtype with transcriptional similarity to bona fide interneurons. C_LIO_LISuccessful glia-to-PV interneuron conversion passes through a specific reprogramming trajectory and involves key genes with functional potential. C_LI

neuroscience↗

bioRxiv2024

Anabolic sensitivity in healthy, lean, older men is associated with higher expression of amino acid sensors and mTORC1 activators

BackgroundSarcopenia is thought to be underlined by age-associated anabolic resistance and dysregulation of intracellular signalling pathways. However, it is unclear whether these phenomena are driven by ageing per se or other confounding factors. MethodsLean and healthy young (n=10, 22 {+/-} 3 yrs, BMI; 23.4 {+/-} 0.8 kg/m2) and old men (n=10, 70 {+/-} 3 yrs, BMI; 22.7 {+/-} 1.3 kg/m2) performed unilateral resistance exercise followed by intake of essential amino acids (EAA). Muscle biopsies were collected from the rested and the exercised leg before, immediately after, as well as 60 and 180 minutes after EAA intake. Muscle samples were analyzed for amino acid concentrations, muscle protein synthesis (MPS) and associated anabolic signaling. ResultsFollowing exercise, peak plasma levels of EAA and leucine were similar between groups, but the area under the curve was [~]11% and [~]28% lower in Young (p<0.01). Absolute levels of muscle EAA and leucine peaked 60 min after exercise, with [~]15 and [~]21 % higher concentrations in the exercising leg (p<0.01) but with no difference between groups. MPS increased in both the resting ([~] 0.035%{middle dot}h-1 to 0.056%{middle dot}h-1, p<0.05) and exercising leg ([~] 0.035%{middle dot}h-1 to 0.083%{middle dot}h-1, p<0.05) with no difference between groups. Phosphorylation of S6K1Thr389 increased to a similar extent in the exercising leg in both groups but was 2.8-fold higher in the resting leg of Old at the 60 min timepoint (p<0.001). Phosphorylation of 4E-BP1Ser65 increased following EAA intake and exercise, but differences between legs were statistically different only at 180 min (p<0.001). However, phosphorylation of this site was on average 78% greater across all timepoints in Old (p<0.01). Phosphorylation of eEF2Thr56 was reduced ([~] 66 and 39%) in the exercising leg at both timepoints after EAA intake and exercise, with no group differences (p<0.05). However, phosphorylation at this site was reduced by [~] 27% also in the resting leg at 60 min, an effect that was only seen in Old (p<0.01). Total levels of Rheb ([~] 45%), LAT1 ([~] 31%) and Rag B ([~] 31%) were higher in Old (p<0.001). ConclusionLean and healthy old men do not manifest AR as evidenced by potent increases in MPS and mTORC1 signalling following EAA intake and exercise. Maintained anabolic sensitivity with age appears to be a function of a compensatory increase in basal levels of proteins involved in anabolic signalling. Therefore, our results suggest that age per se does not appear to cause AR in human skeletal muscle.

physiology↗

bioRxiv2023

T-cell commitment inheritance - an agent-based multi-scale model

T-cell development provides an excellent model system for studying lineage commitment from a multipotent progenitor. The intrathymic development process has been thoroughly studied. The molecular circuitry controlling it has been dissected and the necessary steps like programmed shut off of progenitor genes and T-cell genes upregulation have been revealed. However, the exact timing between decision-making and commitment stage remains unexplored. To this end, we implemented an agent-based multi-scale model to investigate inheritance in early T-cell development. Treating each cell as an agent provides a powerful tool as it tracks each individual cell of a simulated T-cell colony, enabling the construction of lineage trees. Based on the lineage trees, we introduce the concept of the last common ancestors (LCA) of committed cells and analyse their relations, both at single-cell level and population level. In addition to simulating wild-type development, we also conduct knockdown analysis. Our simulations showed that the commitment is a three-step process over several cell generations where a cell is first prepared by a transcriptional switch. This is followed by the loss of the Bcl11b-opposing function two to three generations later which is when the decision to commit is taken. Finally, after another one to two generations, the cell becomes committed by transitioning to the DN2b state. Our results showed that there is inheritance in the commitment mechanism.

systems biology↗

bioRxiv2023

Conservation of affinity rather than sequence underlies a dynamic evolution of the motif-mediated p53/MDM2 interaction in teleosts

The transcription factor and cell cycle regulator p53 is marked for degradation by the ubiquitin ligase MDM2. The interaction between these two proteins is mediated by a conserved binding motif in the disordered p53 transactivation domain (p53TAD) and the folded SWIB domain in MDM2. The conserved motif in p53TAD from zebrafish displays a 20-fold weaker interaction with MDM2, compared to the interaction in human and chicken. To investigate this apparent difference, we tracked the molecular evolution of the p53TAD/MDM2 interaction among ray- finned fishes (Actinopterygii), the largest vertebrate clade. Intriguingly, phylogenetic analyses, ancestral sequence reconstructions, and binding experiments showed that different loss-of- affinity changes in the canonical binding motif within p53TAD have occurred repeatedly and convergently in different fish lineages, resulting in relatively low extant affinities (KD = 0.5-5 M). However, for eleven different fish p53TAD/MDM2 interactions, non-conserved regions flanking the canonical motif increased the affinity 4 to 73-fold to be on par with the human interaction. Our findings suggest that compensating changes at conserved and non-conserved positions within the motif, as well as in flanking regions of low conservation, underlie a stabilizing selection of "functional affinity" in the p53TAD/MDM2 interaction. Such interplay complicates bioinformatic prediction of binding and call for experimental validation. Motif- mediated protein-protein interactions involving short binding motifs and folded interaction domains are very common across multicellular life. It is likely that evolution of affinity in motif- mediated interactions often involves an interplay between specific interactions made by conserved motif residues and non-specific interactions by non-conserved disordered regions.

molecular biology↗

bioRxiv2023

Folded alpha helical putative new proteins from Apilactobacillus kunkeei

The emergence of new proteins is a central question in biology. Most tertiary protein folds known to date appear to have an ancient origin, but it is clear from bioinformatic analyses that new proteins continuously emerge in all organismal groups. However, there is a paucity of experimental data on new proteins regarding their structure and biophysical properties. We performed a detailed phylogenetic analysis and identified 48 putative open reading frames in the honeybee-associated bacterium Apilactobacillus kunkeei for which no homologs could be identified in closely-related species, suggesting that they could be relatively new on an evolutionary time scale and represent recently evolved proteins. Using circular dichroism-, fluorescence- and nuclear magnetic resonance spectroscopy we investigated five of these proteins and show that they are not intrinsically disordered, but populate alpha-helical dominated folded states with relatively low thermodynamic stability (0-3 kcal/mol). The data demonstrate that small new proteins readily adopt simple folded conformations suggesting that more complex tertiary structures can be continuously re-invented during evolution by fusion of such simple secondary structure elements. These findings have implications for the general view on protein evolution, where de novo emergence of folded proteins may be a common event.

molecular biology↗

bioRxiv2023

The evolution of binding affinities between p53 and MDM2 across the animal kingdom demonstrates high plasticity in motif-mediated interactions

The interaction between the transcription factor p53 and the ubiquitin ligase MDM2 results in degradation of p53 and is well studied in cancer biology and drug development. Available sequence data suggest that both p53 and MDM2-family proteins are present across the animal kingdom. However, the interacting regions are missing in some animal groups, and it is not clear whether MDM2 interacts with, and regulates p53 in all species. We used phylogenetic analyses and biophysical measurements to examine the evolution of affinity between the interacting protein regions: a conserved 12-residue intrinsically disordered binding motif in the p53 transactivation domain (TAD) and the folded SWIB domain of MDM2. The affinity varied significantly across the animal kingdom. The p53TAD/MDM2 interaction among jawed vertebrates displayed high affinity, in particular for chicken and human proteins (KD around 0.1 M). The affinity of the bay mussel p53TAD/MDM2 complex was lower (KD = 15 M) and those from a placozoan, an arthropod and a jawless vertebrate were very low or non-detectable (KD > 100 M). Binding experiments with reconstructed ancestral p53TAD/MDM2 variants suggested that a micromolar affinity interaction was present in the ancestral bilaterian animal and was later enhanced in tetrapods while lost in other linages. The different evolutionary trajectories of p53TAD/MDM2 affinity during speciation demonstrate high plasticity of motif-mediated interactions and the potential for rapid adaptation of p53 regulation during times of change. Neutral drift in unconstrained disordered regions may underlie the plasticity and explain the observed low sequence conservation in transactivation domains such as p53TAD. Statement for broader audienceThe protein p53 regulates central cellular processes including cell division and programmed cell death. p53 is regulated by another protein, MDM2, which binds to p53 and marks it for destruction. We measured the interaction between present-day and reconstructed ancient p53 and MDM2 proteins and found a range of binding strengths. Our findings suggest that rapid evolution of the p53/MDM2 interaction facilitates adaptation of p53 regulation during speciation.

molecular biology↗

bioRxiv2022

Identification of motif-based interactions between SARS-CoV-2 protein domains and human peptide ligands pinpoint antiviral targets.

The infection and replication cycle of all viruses depend on interactions between viral and host proteins. Each of these protein-protein interactions is therefore a potential drug target. These host-virus interactions often involve a disordered protein region on one side of the interface and a folded protein domain on the other. Here, we used proteomic peptide phage display (ProP-PD) to identify peptides from the intrinsically disordered regions of the human proteome that bind to folded protein domains encoded by the SARS-CoV-2 genome. Eleven folded domains of SARS-CoV-2 proteins were found to bind peptides from human proteins. Of 281 high/medium confidence peptides, 23 interactions involving eight SARS-CoV-2 protein domains were tested by fluorescence polarization, and binding was observed with affinities spanning the whole micromolar range. The key specificity determinants were established for six of these domains, two based on ProP-PD and four by alanine scanning SPOT arrays. Finally, two cell-penetrating peptides, targeting Nsp9 and Nsp16, respectively, were shown to function as inhibitors of viral replication. Our findings demonstrate how high-throughput peptide binding screens simultaneously provide information on potential host-virus interactions and identify ligands with antiviral properties.

molecular biology↗

bioRxiv2022

Large-scale phage-based screening reveals extensive pan-viral mimicry of host short linear motifs

Viruses mimic host short linear motifs (SLiMs) to hijack and deregulate cellular functions. Studies of motif-mediated interactions therefore provide insight into virus-host dependencies, and reveal targets for therapeutic intervention. Here, we describe the pan-viral discovery of 1,712 SLiM-based virus-host interactions using a phage peptidome tiling the intrinsically disordered protein regions of 229 RNA viruses. We find mimicry of host SLiMs to be a ubiquitous viral strategy, reveal novel host proteins hijacked by viruses, and identify cellular pathways frequently deregulated by viral motif mimicry. Using structural and biophysical analyses, we show that viral mimicry-based interactions have similar binding strength and bound conformations as endogenous interactions. Finally, we establish polyadenylate-binding protein 1 as a potential target for broad-spectrum antiviral agent development. Our platform enables rapid discovery of mechanisms of viral interference and the identification of potential therapeutic targets which can aid in combating future epidemics and pandemics.

biochemistry↗

bioRxiv2022

CELLoGeNe - an Energy Landscape Framework for Logical Networks Controlling Cell Decisions

Experimental and computational efforts are constantly made to elucidate mechanisms controlling cell fate decisions during development and cell reprogramming. One powerful method is to consider cell commitment and reprogramming as movements in an energy landscape. Here, we develop CELLoGeNe (Computation of Energy Landscapes of Logical Gene Networks), which maps Boolean implementation of gene regulatory networks (GRNs) into energy landscapes. CELLoGeNe removes inadvertent symmetries in the energy landscapes normally arising from standard Boolean operators. Furthermore, CELLoGeNe provides a tool for visualising multi-dimensional energy landscapes and a platform to stochastically probe and analyse the shapes of the computed landscapes corresponding to the epigenetic landscapes for development and reprogramming. We demonstrate CELLoGeNe on a GRN governing maintenance and self-renewal of pluripotency, identifying attractors experimentally validated. We also apply CELLoGeNe on a network controlling reprogramming from mouse embryonic fibroblast (MEF) to induced pluripotent stem cells (iPSCs) where we identify potential roadblocks as attractors. CELLoGeNe is a general framework that can be applied to various biological systems offering a broad picture of intracellular dynamics otherwise inaccessible with existing methods.

systems biology↗

bioRxiv2021

The dynamic properties of a nuclear coactivator binding domain are evolutionarily conserved

Evolution of proteins is constrained by their structure and function. While there is a consensus that the plasticity of intrinsically disordered proteins relaxes the structural constraints on evolution there is a paucity of data on the molecular details of these processes. The Nuclear co-activator binding domain (NCBD) from CREB-binding protein is a protein-protein interaction domain, which contains a hydrophobic core but is not behaving as a typical globular domain, and has been desribed as molten-globule like. The highly dynamic properties of NCBD makes it an interesting model system for evolutionary structure-function investigation of intrinsically disordered proteins. We have here compared the structure and biophysical properties of an ancient version of NCBD present in a bilaterian animal ancestor living around 600 million years ago with extant human NCBD. Using a combination of NMR spectroscopy, circular dichroism and kinetic methods we show that although NCBD has increased its thermodynamic stability, it has retained its dynamic biophysical properties in the ligand-free state in the evolutionary lineage leading from the last common bilaterian ancestor to humans. Our findings suggest that the dynamic properties of NCBD have been maintained by purifying selection and thus are important for its function, which includes mediating several distinct protein-protein interactions.

biophysics↗

bioRxiv2021

Large scale discovery of coronavirus-host factor protein interaction motifs reveals SARS-CoV-2 specific mechanisms and vulnerabilities

Viral proteins make extensive use of short peptide interaction motifs to hijack cellular host factors. However, current methods do not identify this important class of protein-protein interactions. Uncovering peptide mediated interactions provides both a molecular understanding of viral interactions with their host and the foundation for developing novel antiviral reagents. Here we describe a scalable viral peptide discovery approach covering 229 RNA viruses that provides high resolution information on direct virus-host interactions. We identify 269 peptide-based interactions for 18 coronaviruses including a specific interaction between the human G3BP1/2 proteins and an {Phi}xFG peptide motif in the SARS-CoV-2 nucleocapsid (N) protein. This interaction supports viral replication and through its {Phi}xFG motif N rewires the G3BP1/2 interactome to disrupt stress granules. A peptide-based inhibitor disrupting the G3BP1/2-N interaction blocks SARS-CoV-2 infection showing that our results can be directly translated into novel specific antiviral reagents.

biochemistry↗

bioRxiv2021

Proteome-scale amino-acid resolution footprinting of protein-binding sites in the intrinsically disordered regions of the human proteome

Specific protein-protein interactions are central to all processes that underlie cell physiology. Numerous studies using a wide range of experimental approaches have identified tens of thousands of human protein-protein interactions. However, many interactions remain to be discovered, and low affinity, conditional and cell type-specific interactions are likely to be disproportionately under-represented. Moreover, for most known protein-protein interactions the binding regions remain uncharacterized. We previously developed proteomic peptide phage display (ProP-PD), a method for simultaneous proteome-scale identification of short linear motif (SLiM)-mediated interactions and footprinting of the binding region with amino acid resolution. Here, we describe the second-generation human disorderome (HD2), an optimized ProP-PD library that tiles all disordered regions of the human proteome and allows the screening of ~1,000,000 overlapping peptides in a single binding assay. We define guidelines for how to process, filter and rank the results and provide PepTools, a toolkit for annotation and analysis of identified hits. We uncovered 2,161 interaction pairs for 35 known SLiM-binding domains and confirmed a subset of 38 interactions by biophysical or cell-based assays. Finally, we show how the amino acid resolution binding site information can be used to pinpoint functionally important disease mutations and phosphorylation events in intrinsically disordered regions of the human proteome. The HD2 ProP-PD library paired with PepTools represents a powerful pipeline for unbiased proteome-wide discovery of SLiM-based interactions.

biochemistry↗

bioRxiv2020

Evolution of an interaction between disordered proteins resulted in increased heterogeneity of the binding transition state

Intrinsically disordered protein (IDP) domains often have multiple binding partners. Little is known regarding molecular changes in the binding mechanism when a new interaction evolves from low to high affinity. Here we compared the degree of native contacts in the transition state of the interaction of two IDP domains, low-affinity ancestral and high-affinity human NCBD and CID. We found that the coupled binding and folding mechanism of the domains is overall similar, but with a higher degree of native hydrophobic contact formation in the transition state of the ancestral complex while more heterogenous transient interactions, including electrostatic, and an increased disorder characterize the human complex. From an evolutionary perspective, adaptation to new binding partners for IDPs may benefit from this ability to exploit multiple alternative transient interactions while retaining the overall pathway.

biophysics↗

bioRxiv2019

Helix formation during the coupled binding and folding of intrinsically disordered proteins monitored by synchrotron-radiation circular dichroism spectroscopy

Intrinsically disordered proteins organize interaction networks in the cell in many regulation and signalling processes. These proteins often gain structure upon binding to their target proteins in multi-step reactions involving the formation of both secondary and tertiary structure. To understand the interactions of disordered proteins, we need to understand the mechanisms of these coupled folding and binding reactions. We studied helix formation in the binding of the molten globule-like nuclear coactivator binding domain (NCBD) and the disordered interaction domain from activator of thyroid hormone and retinoid receptors (ACTR). We demonstrate that helix formation in a rapid binding reaction can be followed by stopped flow synchrotron-radiation circular dichroism spectroscopy, and describe the design of such a beamline. Fluorescence-monitored binding experiments of ACTR and NCBD display several kinetic phases including one concentration-independent phase, which is consistent with an intermediate stabilized at high ionic strength. Time resolved circular dichroism experiments show that almost all helicity is formed upon initial association of the proteins, or separated from the encounter complex by only a small energy barrier. Through simulation of mechanistic models, we show that the intermediate observed at high ionic strength likely involves a structural rearrangement with minor overall changes in helicity. Our experiments provide a benchmark for simulations of coupled binding reactions and demonstrate the feasibility of using synchrotron radiation circular dichroism for mechanistic studies of protein-protein interactions.

biophysics↗

bioRxiv2017

Evolutionary and functional data power search for obsessive-compulsive disorder genes

Obsessive-compulsive disorder (OCD) is a severe psychiatric disorder linked to abnormalities in the cortico-striatal circuit and in glutamate signaling. We sequenced coding and regulatory elements for 608 genes implicated in OCD from humans and two animal models (mouse and dog). Using a new method, PolyStrat, which prioritizes variants disrupting evolutionarily conserved, functional regions, we found four strongly associated genes when comparing 592 cases to 560 controls. These results were validated in a second, larger cohort. NRXN1 and HTR2A are enriched for coding variants altering postsynaptic protein-binding domains, while CTTNBP2 (synapse maintenance) and REEP3 (vesicle trafficking) are enriched for regulatory variants. The rare coding variant burden in NRXN1 achieves genomewide significance (p=6.37x10-11) when we include public data for 33,370 controls. Of 17 regulatory variants identified in CTTNBP2 and REEP3, we show that at least six alter transcription factor-DNA binding in human neuroblastoma cells. Our findings suggest synaptic adhesion as a key function in compulsive behaviors across three species, and demonstrate how combining targeted sequencing with functional annotations can identify potentially causative variants in both coding and noncoding regions, even when genomic data is limited.

genomics↗