Also published as: Amos Adler, Arnon Adler, Charles H Adler, Christina Adler, Dale Adler, Emily E Adler, Eric D Adler, Flavia Adler, Gail K Adler, Heike Adler, Jakob Adler, Jennifer S Adler, Julia Adler, Mart Adler, Priit Adler, Sarah Adler, Thure Adler
Obesity and Alzheimer’s disease (AD) are epidemiologically associated. The locus coeruleus (LC)—the brain’s primary and most significant source of norepinephrine—is one of the earliest sites of neurod Show more
Obesity and Alzheimer’s disease (AD) are epidemiologically associated. The locus coeruleus (LC)—the brain’s primary and most significant source of norepinephrine—is one of the earliest sites of neurodegeneration in AD. The LC participates in feeding behavior through connections with the hypothalamus. The cellular composition of the LC has been characterized at single-cell resolution. However, the constituent cellular signatures of genes related to energy homeostasis—such as the melanocortin pathway genes—in the LC are unclear. We performed single-nucleus RNA sequencing and spatial transcriptomics (Visium) in the human LC, and HiPlex RNAscope in the LC of mice. The melanocortin pathway gene The online version contains supplementary material available at 10.1186/s40478-026-02287-x. Show less
Subjective cognitive complaints (SCC) can precede cognitive decline and are associated with demographic, exposure, lifestyle, and psychological factors. Prevalences of SCC and their correlates in indi Show more
Subjective cognitive complaints (SCC) can precede cognitive decline and are associated with demographic, exposure, lifestyle, and psychological factors. Prevalences of SCC and their correlates in individuals with repetitive head impacts (RHI) are poorly understood. This study characterized SCC in former elite American football players by frequency, mood and behavioral correlates, concordance with informant reports, and associations with neuropsychological test performance, cerebrospinal fluid (CSF), and magnetic resonance imaging (MRI) markers of neurodegeneration. Former American football players ( Rates of SCC ranged from 43 to 77% depending on the domain. Symptoms of depression, impulsivity, and anxiety were strongly associated with SCC. Self- and informant-reported SCC showed moderate inter-rater agreement. Adjusting for age, race, education, SCC are strongly associated with neuropsychiatric factors in former American football players. SCC may also be a marker of cognitive decline and neurodegeneration. Show less
Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease associated with exposure to repetitive head impacts (RHIs), characterized by tau tangles around small blood vessels at the depths Show more
Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease associated with exposure to repetitive head impacts (RHIs), characterized by tau tangles around small blood vessels at the depths of the sulci. Currently, CTE can be diagnosed only Show less
Persons with human immunodeficiency virus (HIV) well-treated on antiretrovirals have increased arterial inflammation, which can lead to development of atherosclerotic disease. We have previously shown Show more
Persons with human immunodeficiency virus (HIV) well-treated on antiretrovirals have increased arterial inflammation, which can lead to development of atherosclerotic disease. We have previously shown that treatment with eplerenone can significantly reduce arterial inflammation, as measured by target-to-background ratio (TBR) on cardiac We performed a targeted discovery-based approach to identify a proteomics signature associated with eplerenone treatment that may provide a plausible mechanism for the reduction in arterial inflammation. In an exploratory study, we leveraged analyzable samples from participants who completed the 12-month, placebo-controlled, randomized controlled trial MIRABELLA HIV to evaluate 276 proteins (Olink Target 96 Cardiometabolic, Cardiovascular II, Cardiovascular III), with relevance to cardiovascular and cardiometabolic disease. We identified 11 proteins that differed in expression between treatment groups. Eight proteins (CDH1, CES1, ADM, IL-4RA, FGF-21, FS, FABP2, Gal-4) decreased and 2 proteins increased (CSTB, MPO) in expression with eplerenone compared to placebo. An increase in expression of IL-27 was prevented among eplerenone-treated versus placebo-treated groups. Changes in TBR of the most diseased segment of the index vessel correlated with changes in 3 of these proteins: CDH1 (ρ = 0.53, Through this proteomics approach, we discovered that 3 key proteins, CDH1, FGF-21, and Gal-4, are decreased in parallel with reductions in arterial inflammation after treatment with eplerenone. Eplerenone-induced reductions in these proteins, known to be related to inflammation, epithelial barrier disruption, vascular dysfunction, and metabolic dysregulation, provide mechanistic insight into pathways by which eplerenone may improve cardiovascular disease in HIV. NCT02740179. Show less
Electronic health records will increasingly aggregate longitudinal laboratory results from multiple providers, but availability alone does not guarantee safe interpretation. We present guidance, devel Show more
Electronic health records will increasingly aggregate longitudinal laboratory results from multiple providers, but availability alone does not guarantee safe interpretation. We present guidance, developed by laboratory professionals with the DGKL medical informatics division, for cumulative displays that are clinically meaningful. The core principle is to group medically comparable analyses while preserving laboratory provenance so that clinicians can follow true patient trends without conflating them with laboratory-induced variation. Comparability is defined algorithmically from Logical Observation Identifiers Names and Codes (LOINC) axis: analyses estimating the same patient property (allowing serum/plasma system equivalence and mathematically convertible properties such as substance vs. mass concentration) are grouped; coding of units is harmonized via Unified Code for Units of Measure (UCUM) with consistent conversion of numeric results and corresponding reference intervals, including inequality qualifiers. Analyte-specific conversion factors should come from authoritative sources; for poorly standardized measurands (e.g., tumor markers) or when conversions are inappropriate (e.g., Lp(a)), results remain separated. Methodological distinctions that affect interpretation - such as screening vs. confirmatory drug testing and point-of-care testing - are displayed independently to signal potential analytical discontinuities. A standardized, medically meaningful default result sequence - derived from LOINC metadata and clinical nomenclatures, with alphabetic naming as a pragmatic fallback - supports cross-laboratory aggregation; rare or novel tests lacking robust standardization remain as free text. The rules-based approach updates seamlessly with LOINC releases and remains compatible with the Nomenclature for Properties and Units (NPU), facilitating cross-border exchange within the European Health Data Space. While harmonized presentation improves trend analysis, true comparability ultimately requires measurement procedures traceable to reference methods and materials. Show less
Hypertrophic cardiomyopathy (HCM) is an important cause of morbidity and mortality with both monogenic and polygenic components. Here, we report results from a large genome-wide association study and Show more
Hypertrophic cardiomyopathy (HCM) is an important cause of morbidity and mortality with both monogenic and polygenic components. Here, we report results from a large genome-wide association study and multitrait analysis including 5,900 HCM cases, 68,359 controls and 36,083 UK Biobank participants with cardiac magnetic resonance imaging. We identified 70 loci (50 novel) associated with HCM and 62 loci (20 novel) associated with relevant left ventricular traits. Among the prioritized genes in the HCM loci, we identify a novel HCM disease gene, SVIL, which encodes the actin-binding protein supervillin, showing that rare truncating SVIL variants confer a roughly tenfold increased risk of HCM. Mendelian randomization analyses support a causal role of increased left ventricular contractility in both obstructive and nonobstructive forms of HCM, suggesting common disease mechanisms and anticipating shared response to therapy. Taken together, these findings increase our understanding of the genetic basis of HCM, with potential implications for disease management. Show less
Fibroblast growth factor receptors (FGFRs; FGFR1, FGFR2, FGFR3, FGFR4) are frequently mutated oncogenes in solid cancers. The oncogenic potential of FGFR rearrangements and few hotspot point mutations Show more
Fibroblast growth factor receptors (FGFRs; FGFR1, FGFR2, FGFR3, FGFR4) are frequently mutated oncogenes in solid cancers. The oncogenic potential of FGFR rearrangements and few hotspot point mutations is well established, but the majority of variants resulting from point mutations especially outside of the tyrosine kinase domain are currently considered variants of unknown significance (VUS). Recurrent nonkinase domain FGFR VUS variants were collected from the Catalog of Somatic Mutations in Cancer and their oncogenic potential was assessed in vitro by different functional assays. We compiled published clinical and preclinical data on FGFR variants and compared the data with results from our functional assays and pathogenicity predictions of state-of-the-art artificial intelligence (AI) models. We identified 12 novel FGFR extracellular small variants with potential driver function. Comparison of clinical and preclinical data on FGFR variants with pathogenicity predictions of state-of-the-art AI models showed limited usefulness of the AI predictions. Sensitivity profiles of activating FGFR variants to targeted inhibitors were recorded and showed good targetability of FGFR nonkinase domain variants. The collected results extend the spectrum of suitable FGFR variants for potential treatment with FGFR inhibitors in the context of clinical trials and beyond. Current AI models for variant pathogenicity prediction require further refinement for use in oncogenic decision making. Show less
Genetic cardiomyopathies (CMs) are increasingly recognized as causes of end-stage heart failure (ESHF). Identification of a genetic etiology in ESHF has important prognostic and family implications. H Show more
Genetic cardiomyopathies (CMs) are increasingly recognized as causes of end-stage heart failure (ESHF). Identification of a genetic etiology in ESHF has important prognostic and family implications. However, genetic testing practices are understudied in patients with ESHF. This single-center, retrospective study included consecutive patients with ESHF who underwent heart transplantation (HT) or left ventricular assist device (LVAD) implantation between 2018 and 2023. Data, including genetic testing and pathology reports, were collected from the electronic medical records. Analyses of demographic and clinical characteristics were stratified by genetic-testing completion and the presence of clinically actionable variants. Logistic regression was performed to evaluate for associations between histology findings and genetic variants. A total of 529 adult patients (mean age 57 years) were included in the study and were predominantly male (79%, 422/529) and non-white (61%, 322/529). Genetic testing was performed in 54% (196/360) of patients with either nonischemic or mixed CMs. A clinically actionable result was identified in 36% (70/196) of patients, of whom only 43% (30/70) had genetic counselor referrals. The most common genetic variants were TTN (32%, 24/75), MYBPC3 (13%, 10/75) and TTR (11%, 8/75). Clinically actionable variants were identified in patients with known heart failure precipitators such as alcohol use. In multivariable analysis, the presence of interstitial fibrosis, specifically diffuse, on pathology was significantly associated with a clinically actionable variant (aOR 2.29, 95% CI [1.08-4.86]; P = 0.03). Patients with ESHF and with nonischemic or mixed CM who were undergoing advanced therapies had low uptakes of genetic services, including testing and counselors, despite high burdens of genetic disease. Pathology findings such as interstitial fibrosis may provide insight into genetic etiology. The underuse of services suggests a need for implementation strategies to improve uptake. Show less
Although KRASG12C inhibitors show clinical activity in patients with KRAS G12C mutated non-small cell lung cancer (NSCLC) and other solid tumor malignancies, response is limited by multiple mechanisms Show more
Although KRASG12C inhibitors show clinical activity in patients with KRAS G12C mutated non-small cell lung cancer (NSCLC) and other solid tumor malignancies, response is limited by multiple mechanisms of resistance. The KRASG12C inhibitor JDQ443 shows enhanced preclinical antitumor activity combined with the SHP2 inhibitor TNO155, and the combination is currently under clinical evaluation. To identify rational combination strategies that could help overcome or prevent some types of resistance, we evaluated the duration of tumor responses to JDQ443 ± TNO155, alone or combined with the PI3Kα inhibitor alpelisib and/or the cyclin-dependent kinase 4/6 inhibitor ribociclib, in xenograft models derived from a KRASG12C-mutant NSCLC line and investigated the genetic mechanisms associated with loss of response to combined KRASG12C/SHP2 inhibition. Tumor regression by single-agent JDQ443 at clinically relevant doses lasted on average 2 weeks and was increasingly extended by the double, triple, or quadruple combinations. Growth resumption was accompanied by progressively increased KRAS G12C amplification. Functional genome-wide CRISPR screening in KRASG12C-dependent NSCLC lines with distinct mutational profiles to identify adaptive mechanisms of resistance revealed sensitizing and rescuing genetic interactions with KRASG12C/SHP2 coinhibition; FGFR1 loss was the strongest sensitizer, and PTEN loss the strongest rescuer. Consistently, the antiproliferative activity of KRASG12C/SHP2 inhibition was strongly enhanced by PI3K inhibitors. Overall, KRAS G12C amplification and alterations of the MAPK/PI3K pathway were predominant mechanisms of resistance to combined KRASG12C/SHP2 inhibitors in preclinical settings. The biological nodes identified by CRISPR screening might provide additional starting points for effective combination treatments. Identification of resistance mechanisms to KRASG12C/SHP2 coinhibition highlights the need for additional combination therapies for lung cancer beyond on-pathway combinations and offers the basis for development of more effective combination approaches. See related commentary by Johnson and Haigis, p. 4005. Show less
Activating Transcription Factor 4 (ATF4) is an important regulator of gene expression in stress responses and developmental processes in many cell types. Here, we catalogued ATF4 binding sites in the Show more
Activating Transcription Factor 4 (ATF4) is an important regulator of gene expression in stress responses and developmental processes in many cell types. Here, we catalogued ATF4 binding sites in the human genome and identified overlaps with trait-associated genetic variants. We probed these genetic variants for allelic regulatory activity using a massively parallel reporter assay (MPRA) in HepG2 hepatoma cells exposed to tunicamycin to induce endoplasmic reticulum stress and ATF4 upregulation. The results revealed that in the majority of cases, the MPRA allelic activity of these SNPs was in agreement with the nucleotide preference seen in the ATF4 binding motif from ChIP-Seq. Luciferase and electrophoretic mobility shift assays in additional cellular models further confirmed ATF4-dependent regulatory effects for the SNPs rs532446 (GADD45A intronic; linked to hematological parameters), rs7011846 (LPL upstream; myocardial infarction), rs2718215 (diastolic blood pressure), rs281758 (psychiatric disorders) and rs6491544 (educational attainment). CRISPR-Cas9 disruption and/or deletion of the regulatory elements harboring rs532446 and rs7011846 led to the downregulation of GADD45A and LPL, respectively. Thus, these SNPs could represent examples of GWAS genetic variants that affect gene expression by altering ATF4-mediated transcriptional activation. Show less
In the absence of universal screening for congenital cytomegalovirus (cCMV) infection, the aim of this study was to assess the outcomes of a targeted screening protocol based on maternal and neonatal Show more
In the absence of universal screening for congenital cytomegalovirus (cCMV) infection, the aim of this study was to assess the outcomes of a targeted screening protocol based on maternal and neonatal risk indicators. The medical records of 2,623 neonates born in our maternal hospital between June 2016 and December 2018 and screened for cCMV infection were reviewed. Among those of the included neonates, the records of 380 CMV-negative and 19 CMV-positive neonates were randomly assigned to obtain additional comparative data. During the study period, a total of 63 neonates were identified as positive for cCMV, comprising 0.2% of the total birth cohort (63/28,982) and 2.4% of all neonates screened for cCMV (63/2,623). The comparative data analysis showed that suspected or confirmed CMV infection during pregnancy, maternal age, and maternal diabetes mellitus were found to be significantly associated with a positive cCMV diagnosis. Although symmetric small for gestational age and hearing screening failure contributed to the detection of some of the CMV-positive infants, these factors were not specific to this group. The results of the logistic regression model showed that the only factor that was significantly associated with an increased risk for a cCMV diagnosis was maternal serology suspected of CMV infection during pregnancy, with a regression coefficient estimate of 2.657 (adjusted p < 0.001). A targeted neonatal screening protocol based on multiple maternal and neonatal risk indicators is feasible but provides limited information. Our study emphasizes the importance of universal neonatal screening for the detection of neonates with cCMV. Show less
Testosterone (T) is a central androgenic hormone, and sex hormone-binding globulin (SHBG) is the major determinant of its bioactivity. There are no acknowledged genetic variants with clear-cut clinica Show more
Testosterone (T) is a central androgenic hormone, and sex hormone-binding globulin (SHBG) is the major determinant of its bioactivity. There are no acknowledged genetic variants with clear-cut clinical implications, modulating T levels in men. To confirm genetic associations of top loci ( Groups differing in general and reproductive parameters: young men (n = 540; 19.3 ± 1.8 years), severe idiopathic male infertility patients (n = 641; 31.6 ± 6.0 years), and male partners of pregnant women (n = 324; 31.9 ± 6.6 years). All patients were recruited at the Andrology Centre, Tartu University Hospital, Estonia. Genetic associations with reproductive hormones, testicular and sperm parameters (linear regression, additive model); intergroup allele/genotype distribution comparisons. Associations with serum SHBG levels were robust for Claims were replicated and additional associations were detected for four of seven tested GWAS top loci. Perspective clinical investigations of these variants are hypotestosteronemia among aging men and pharmacogenetics of hormone replacement therapy. Show less
As DNA sequencing costs decline, genetic testing options have expanded. Whole exome sequencing and whole genome sequencing (WGS) are entering clinical use, posing questions about their incremental val Show more
As DNA sequencing costs decline, genetic testing options have expanded. Whole exome sequencing and whole genome sequencing (WGS) are entering clinical use, posing questions about their incremental value compared with disease-specific multigene panels that have been the cornerstone of genetic testing. Forty-one patients with hypertrophic cardiomyopathy who had undergone targeted hypertrophic cardiomyopathy genetic testing (either multigene panel or familial variant test) were recruited into the MedSeq Project, a clinical trial of WGS. Results from panel genetic testing and WGS were compared. In 20 of 41 participants, panel genetic testing identified variants classified as pathogenic, likely pathogenic, or uncertain significance. WGS identified 19 of these 20 variants, but the variant detection algorithm missed a pathogenic 18 bp duplication in myosin binding protein C ( WGS detected nearly all variants identified on panel testing, provided 1 new diagnostic finding, and allowed interrogation of posited disease genes. Several variants of uncertain clinical use and numerous secondary genetic findings were also identified. Whereas panel testing and WGS provided similar diagnostic yield, WGS offers the advantage of reanalysis over time to incorporate advances in knowledge, but requires expertise in genomic interpretation to appropriately incorporate WGS into clinical care. URL: https://clinicaltrials.gov. Unique identifier: NCT01736566. Show less
Kaoru Ito, Parth N Patel, Joshua M Gorham+9 more · 2017 · Proceedings of the National Academy of Sciences of the United States of America · National Academy of Sciences · added 2026-04-24
Genetic variants that cause haploinsufficiency account for many autosomal dominant (AD) disorders. Gene-based diagnosis classifies variants that alter canonical splice signals as pathogenic, but due t Show more
Genetic variants that cause haploinsufficiency account for many autosomal dominant (AD) disorders. Gene-based diagnosis classifies variants that alter canonical splice signals as pathogenic, but due to imperfect understanding of RNA splice signals other variants that may create or eliminate splice sites are often clinically classified as variants of unknown significance (VUS). To improve recognition of pathogenic splice-altering variants in AD disorders, we used computational tools to prioritize VUS and developed a cell-based minigene splicing assay to confirm aberrant splicing. Using this two-step procedure we evaluated all rare variants in two AD cardiomyopathy genes, lamin A/C ( Show less
Available data suggests that double mutations in patients with hypertrophic cardiomyopathy are not rare and are associated with a more severe phenotype. Most of this data, however, is based on noncont Show more
Available data suggests that double mutations in patients with hypertrophic cardiomyopathy are not rare and are associated with a more severe phenotype. Most of this data, however, is based on noncontemporary variant classification. Clinical data of all hypertrophic cardiomyopathy patients with 2 rare genetic variants were retrospectively reviewed and compared with a group of patients with a single disease-causing variant. Furthermore, a literature search was performed for all studies with information on prevalence and outcome of patients with double mutations. Classification of genetic variants was reanalyzed according to current guidelines. In our cohort (n=1411), 9% of gene-positive patients had 2 rare variants in sarcomeric genes but only in 1 case (0.4%) were both variants classified as pathogenic. Patients with 2 rare variants had a trend toward younger age at presentation when compared with patients with a single mutation. All other clinical variables were similar. In data pooled from cohort studies in the literature, 8% of gene-positive patients were published to have double mutations. However, after reanalysis of reported variants, this prevalence diminished to 0.4%. All patients with 2 radical mutations in Double mutations in patients with hypertrophic cardiomyopathy are much less common than previously estimated. With the exception of double radical Show less
Cln3(Δex7/8) mice harbor the most common genetic defect causing juvenile neuronal ceroid lipofuscinosis (JNCL), an autosomal recessive disease involving seizures, visual, motor and cognitive decline, Show more
Cln3(Δex7/8) mice harbor the most common genetic defect causing juvenile neuronal ceroid lipofuscinosis (JNCL), an autosomal recessive disease involving seizures, visual, motor and cognitive decline, and premature death. Here, to more thoroughly investigate the manifestations of the common JNCL mutation, we performed a broad phenotyping study of Cln3(Δex7/8) mice. Homozygous Cln3(Δex7/8) mice, congenic on a C57BL/6N background, displayed subtle deficits in sensory and motor tasks at 10-14 weeks of age. Homozygous Cln3(Δex7/8) mice also displayed electroretinographic changes reflecting cone function deficits past 5 months of age and a progressive decline of retinal post-receptoral function. Metabolic analysis revealed increases in rectal body temperature and minimum oxygen consumption in 12-13 week old homozygous Cln3(Δex7/8) mice, which were also seen to a lesser extent in heterozygous Cln3(Δex7/8) mice. Heart weight was slightly increased at 20 weeks of age, but no significant differences were observed in cardiac function in young adults. In a comprehensive blood analysis at 15-16 weeks of age, serum ferritin concentrations, mean corpuscular volume of red blood cells (MCV), and reticulocyte counts were reproducibly increased in homozygous Cln3(Δ) (ex7/8) mice, and male homozygotes had a relative T-cell deficiency, suggesting alterations in hematopoiesis. Finally, consistent with findings in JNCL patients, vacuolated peripheral blood lymphocytes were observed in homozygous Cln3(Δ) (ex7/8) neonates, and to a greater extent in older animals. Early onset, severe vacuolation in clear cells of the epididymis of male homozygous Cln3(Δ) (ex7/8) mice was also observed. These data highlight additional organ systems in which to study CLN3 function, and early phenotypes have been established in homozygous Cln3(Δ) (ex7/8) mice that merit further study for JNCL biomarker development. Show less
Sarah Adler, Cristian Pellizzer, Lars Hareng+2 more · 2008 · Toxicology in vitro : an international journal published in association with BIBRA · Elsevier · added 2026-04-24
The use of embryonic stem cells is currently the most promising approach to assess developmental toxicity in vitro. In addition, the possibility of using human embryonic stem (hES) cells will increase Show more
The use of embryonic stem cells is currently the most promising approach to assess developmental toxicity in vitro. In addition, the possibility of using human embryonic stem (hES) cells will increase safety of consumers and patients as false classification of substances due to inter-species variations can be avoided. One validated test based on murine embryonic stem cells, the embryonic stem cell test (EST), consists of following endpoints: IC(50) values of fibroblasts and embryonic stem cells as well as the inhibition of differentiation of mES cells into cardiomyocytes. As a follow up of its successful validation study we established a cytotoxicity assay based on hES cells and human fibroblasts employing two developmental toxicants: 5-fluorouracil (5-FU) and all-trans retinoic acid (RA). The results were compared to historical data from the EST. For 5-FU, no significant differences were obtained between the different cell lines. However, for RA, both test systems produced higher IC(50) values for the fibroblasts than for the stem cells, which is a well-known effect of developmental toxicants. Moreover, the reliability and relevance of several marker genes as possible toxicological endpoints were tested. During early differentiation Oct-4, hTert and Dusp6 showed the most reliable results. Brachyury and GATA-4 were found to be best suited to monitor cardiac differentiation. The late cardiac marker gene TNNT2 demonstrated significant results until day 18. Therefore, these marker genes have the highest potential to serve as endpoints for a developmental toxicity test. Show less
To date, only the H1 MAPT haplotype has been consistently associated with risk of developing the neurodegenerative disease progressive supranuclear palsy (PSP). We hypothesized that additional genetic Show more
To date, only the H1 MAPT haplotype has been consistently associated with risk of developing the neurodegenerative disease progressive supranuclear palsy (PSP). We hypothesized that additional genetic loci may be involved in conferring risk of PSP that could be identified through a pooling-based genomewide association study of >500,000 SNPs. Candidate SNPs with large differences in allelic frequency were identified by ranking all SNPs by their probe-intensity difference between cohorts. The MAPT H1 haplotype was strongly detected by this methodology, as was a second major locus on chromosome 11p12-p11 that showed evidence of association at allelic (P<.001), genotypic (P<.001), and haplotypic (P<.001) levels and was narrowed to a single haplotype block containing the DNA damage-binding protein 2 (DDB2) and lysosomal acid phosphatase 2 (ACP2) genes. Since DNA damage and lysosomal dysfunction have been implicated in aging and neurodegenerative processes, both genes are viable candidates for conferring risk of disease. Show less
NAD(P)H quinone oxidoreductase 1 (NQO1) is a ubiquitous flavoenzyme that catalyzes two-electron reduction of quinones to hydroquinones utilizing NAD(P)H as an electron donor. NQO1 binds and stabilizes Show more
NAD(P)H quinone oxidoreductase 1 (NQO1) is a ubiquitous flavoenzyme that catalyzes two-electron reduction of quinones to hydroquinones utilizing NAD(P)H as an electron donor. NQO1 binds and stabilizes several short-lived proteins including the tumor suppressors p53 and p73 and the enzyme ornithine decarboxylase (ODC). Dicoumarol is a widely used potent competitive inhibitor of NQO1 enzymatic activity, which competes with NAD(P)H for binding to NQO1. Dicoumarol also disrupts the binding of NQO1 to p53, p73, and ODC and induces their ubiquitin-independent proteasomal degradation. We report here the crystal structure of human NQO1 in complex with dicoumarol at 2.75 A resolution. We have identified the interactions of dicoumarol with the different residues of NQO1 and the conformational changes imposed upon dicoumarol binding. The most prominent conformational changes that occur in the presence of dicoumarol involve Tyr 128 and Phe 232 that are present on the surface of the NQO1 catalytic pocket. On the basis of the comparison of the NQO1 structure in complex with different NQO1 inhibitors and our previous analysis of NQO1 mutants, we propose that the specific conformation of Tyr 128 and Phe 232 is important for NQO1 interaction with p53 and other client proteins. Show less