Search PubMedSearch

SEARCH · Search PubMed

Results for “Research Support, N.I.H., Intramural”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources

Programmed ribosomal frameshifting during PLEKHM2 mRNA decoding generates a constitutively active proteoform that supports myocardial function.

Programmed ribosomal frameshifting is a process where a proportion of ribosomes change their reading frame on an mRNA. While frameshifting is commonly used by viruses, very few phylogenetically conserved examples are known in nuclear encoded genes. Here, we report a +1 frameshifting event during decoding of the human gene PLEKHM2 that provides access to a second internally overlapping ORF. The new carboxyl-terminal domain of this frameshift protein forms an α helix, which relieves PLEKHM2 from autoinhibition and allows it to move to the tips of cells without activation by ARL8. Reintroducing both the canonically translated and frameshifted protein are necessary to restore normal contractile function of PLEKHM2 knockout cardiomyocytes, demonstrating the necessity of frameshifting for normal cardiac activity.

Frameshifting, Ribosomal

Autism ableism seen through research abstract contents: A mixed-methods analysis of language in NIH-funded genetic and genomic autism research.

In recent years, genetic and genomic autism research has come under increasing scrutiny, moving to the center of debates about ableism, neurodiversity, autism acceptance, and the future of research and care. At the same time, both autism research and genetics and genomics research have, as fields, begun to reckon with the significance of the language researchers use in the course of their work and the harmful ideas that may thereby be reinforced. Although the language of research cannot be assumed to straightforwardly correspond to individual researchers' beliefs, the presence of widespread ableist language may indicate structural and institutionalized ableism, including ableist assumptions at the foundations of research. We conducted a mixed-methods analysis of 166 genetic and genomic autism research projects funded by the US National Institutes of Health, in order to understand the prevalence of potentially ableist discourse, language, and stigmatizing language about autistic people. We found that such discourse and language was ubiquitous across our sample, including a discourse of prevention. This study lends empirical evidence to current debates about language in autism research. Evaluating language can prompt researchers and institutions to reflect on how they conceptualize, design, discuss, and pursue their work.Lay abstractGenetic research about autism is controversial. Researchers are starting to think more carefully about the words they use to talk about autism and the way they do their research. Past research has found that researchers sometimes write about autism in ableist ways. This means that they write about autistic people as though they are less important than nonautistic people. We looked at the way genetics researchers have written about autism in the paperwork for their research. We found that they often write about autistic people in an ableist way. We think that researchers should think carefully about the way they write about autistic people, and how they plan and do their research.

Humans

iSoMAs: Finding isoform expression and somatic mutation associations in human cancers.

Aberrant alternative splicing, prevalent in cancer, impacts various cancer hallmarks involving proliferation, angiogenesis, and invasion. Splicing disruption often results from somatic point mutations rewiring functional pathways to support cancer cell survival. We introduce iSoMAs (iSoform expression and somatic Mutation Association), an efficient computational pipeline leveraging principal component analysis technique, to explore how somatic mutations influence transcriptome-wide gene expression at the isoform level. Applying iSoMAs to 33 cancer types comprising 9,738 tumor samples in The Cancer Genome Atlas, we identified 908 somatically mutated genes significantly associated with altered isoform expression across three or more cancer types. Mutations linked to differential isoform expression occurred through both cis- and trans-acting mechanisms, involving well-known oncogenes/suppressor genes, RNA binding protein and splicing factor genes. With wet-lab experiments, we verified direct association between TP53 mutations and differential isoform expression in cell cycle genes. Additional iSoMAs genes have been validated in the literature with independent cohorts and/or methods. Despite the complexity of cancer, iSoMAs attains computational efficiency via dimension reduction strategy and reveals critical associations between regulatory factors and transcriptional landscapes.

Humans

Okazaki fragment maturation involves α-segment error editing by the mammalian FEN1/MutSα functional complex.

During nuclear DNA replication, proofreading-deficient DNA polymerase α (Pol α) initiates Okazaki fragment synthesis with lower fidelity than bulk replication by proofreading-proficient Pol δ or Pol ε. Here, we provide evidence that the exonuclease activity of mammalian flap endonuclease (FEN1) excises Pol α replication errors in a MutSα-dependent, MutLα-independent mismatch repair process we call Pol α-segment error editing (AEE). We show that MSH2 interacts with FEN1 and facilitates its nuclease activity to remove mismatches near the 5' ends of DNA substrates. Mouse cells and mice encoding FEN1 mutations display AEE deficiency, a strong mutator phenotype, enhanced cellular transformation, and increased cancer susceptibility. The results identify a novel role for FEN1 in a specialized mismatch repair pathway and a new cancer etiological mechanism.

Animals

Genomic determinants of antibiotic resistance for Helicobacter pylori treatment: a retrospective phenotypic and genotypic observational study.

BACKGROUND: Rising antimicrobial resistance of Helicobacter pylori is a public health challenge. Genomic-based susceptibility testing allows for the identification of resistance-associated mutations, complementing conventional diagnostics and advancing towards pathogen-based personalised therapies. Our study aimed to identify genes and mutations involved in antimicrobial resistance in H pylori and evaluate the extent to which these markers can be used as predictors of phenotypic resistance against clarithromycin and levofloxacin. METHODS: In this retrospective phenotypic and genotypic observational study, we included 1011 H pylori whole-genome sequences and strains of known geographical origin from the H pylori Genome Project (HpGP) collection. We performed phenotypic clarithromycin and levofloxacin susceptibility testing on a subset of 419 HpGP strains using Etest at a centralised laboratory. A genomic analysis was conducted to identify 23S rRNA and gyrA variants and build a curated catalogue of mutations associated with resistance to clarithromycin (ie, 23S rRNA 2142A→G, 2142A→C, and 2143A→G) and levofloxacin (ie, gyrA A88V or A88P, N87K or N87I, and D91G, D91N, or D91Y). Genotype-phenotype concordance was assessed to estimate sensitivity and specificity, and the curated catalogue of resistance-associated mutations was applied to the complete HpGP set. Region-specific prevalence of resistance-associated mutations was calculated for a combined dataset including the HpGP genomes and 768 whole-genome sequences retrieved from the US National Center for Biotechnology Information Sequence Read Archive repository. Associations between resistance genotypes, H pylori subpopulations, and minimum inhibitory concentrations (MICs) were tested. FINDINGS: Clarithromycin-resistant and levofloxacin-resistant HpGP strains were estimated with a sensitivity and specificity of 100%, with all confidence intervals ranging from 96% to 100%. The combined analysis (n=1779) found the highest prevalence of clarithromycin resistance in the western Pacific region (173 [51·2%] of 338 in southeast Asia and 75 [29·8%] of 252 in eastern Asia), north African region (seven [38·9%] of 18), and western Asian region (12 [31·6%] of 38), whereas the highest prevalence of levofloxacin resistance was found in south Asia (14 [51·85%] of 27), Central America (48 [38·7%] of 124), eastern Europe (four [36·4%] of 11), and southern Africa (three [33·3%] of nine). Similarly, 23S rRNA and gyrA genotypes are variable across H pylori subpopulations. MIC values changed depending on the specific mutation in 23S rRNA (mean clarithromycin MIC 24·61 mg/L [95% CI 12·27-36·96] for 2143A→G and 142·25 mg/L [95% CI 77·88-206·61] for 2142A→G) and gyrA (mean levofloxacin MIC 9·66 mg/L [95% CI 6·75-12·56] for mutations on codon 91, and 27·97 mg/L [95% CI 25·82-30·11] for mutations on codon 87). INTERPRETATION: Mutations in specific genes are reliable indicators to clarithromycin and levofloxacin resistance in H pylori, making them useful markers for the development of diagnostic assays and molecular monitoring. Our results suggest that using clarithromycin and levofloxacin empirically, without previous susceptibility testing, is unsuitable in all geographical regions covered by this study. FUNDING: Intramural Research Program of the US National Cancer Institute, the European Research Council, and the Spanish Ministry of Science and Innovation.

Helicobacter pylori

Sites in the AAV5 capsid tolerant to deletions and tandem duplications.

Gene therapy vectors based on adeno-associated virus (AAV) have shown much promise in clinical trials for the treatment of a variety of diseases. However, the ability to manipulate and engineer the viral surface for enhanced efficiency is necessary to overcome such barriers as pre-existing immunity and transduction of non-target cells that currently limit AAV applications. Although single amino acid changes and peptide insertions at select sites have been explored previously, the tolerance of AAV to small deletions and tandem duplications of sequence has not been globally addressed. Here, we have generated a large, diverse library of >10(5) members containing deletions and tandem duplications throughout the viral capsid of AAV5. Four unique mutants were identified that maintain the ability to form viral particles, with one showing improved transduction on both 293T and BEAS-2B cells. This approach may find potential use for the generation of novel variants with improved and altered properties or in the identification of sites that are tolerant to insertions of targeting ligands.

Amino Acid Sequence

Chromatin remodeling activity of EP400 safeguards chromosomal stability by preventing CENP-A mislocalization.

The mislocalization of CENP-A to non-centromeric regions contributes to chromosomal instability (CIN). The NuA4 histone acetyltransferase complex members EP400 and KAT5 regulate histone H2A.Z-H2B exchange and acetylation of histones, respectively. Overexpression of CENP-A and mutations in NuA4 components are observed in cancers. Here, we define a role for the chromatin remodeling activity of EP400, a top hit in RNAi screens for increased nuclear levels of CENP-A, in preventing CENP-A mislocalization and CIN. Mechanistically, we demonstrate a defect in the extraction of CENP-A from chromatin in cells expressing the EP400K1085G mutant, which lacks ATPase activity for histone exchange. Consistent with these results, EP400K1085G cells show increased CENP-A enrichment in chromatin and mislocalization to non-centromeric regions. Importantly, EP400K1085G cells exhibit CIN phenotypes in stable, near-diploid RPE1 cells with wild-type p53. In summary, our findings expand the role of EP400 from nucleosome destabilization for histone exchange to preventing the stable association of CENP-A with non-centromeric regions and CIN.

Humans

Single-cell RNA-seq of small-intestinal neuroendocrine tumors reveals the cell of origin and gene expression of early tumor development.

Patients with a hereditary form of small-intestinal neuroendocrine tumors (SI-NETs) present with multiple synchronous tumors and precursors at various stages. Using this germline trait, single-cell RNA sequencing is performed to define the cell-of-origin and gene-expression trajectory in early tumor development. A subset of CES1(+), LCN15(-) enterochromaffin (EC) cells, residing at +4 position and below in the crypts, distinct from EC cells migrating up the villi, emerges as the putative SI-NET origin. PRODH2 is identified as a key biomarker for precursor cells, revealing stage-specific gene expression linked to early tumor development. From precursor to fully developed tumors, notable changes include the up-regulation of UCHL1 and MBD3L2, as well as the significant down-regulation of cell-cycle inhibitory genes, CDKN1A, CDKN1C, and CDKN2B, which play roles in cell survival and tumorigenesis. The current study provides insight into SI-NET initiation and progression, offering potential advancements in diagnosis, prevention, and treatment.

Neuroendocrine Tumors

Single-cell glycome and transcriptome profiling enabled by a library of anti-glycan antibodies.

Glycans play critical roles in cellular processes and clinical applications, but they remain difficult to study due to a shortage of well-characterized anti-glycan reagents and high-throughput technologies for glycome profiling, especially ones capable of single-cell resolution. To meet these needs, we generated a database of 650 anti-glycan antibody sequences, recombinantly expressed a library of 154 antibodies, and extensively characterized their binding properties using glycan microarrays. In addition to providing valuable information and resources for the field, the sequence database and microarray data also enabled development of "Glycomic-seq" (Glycome profiling via multiplexed immunoglobulins combined with sequencing), a DNA-barcoded anti-glycan antibody platform that enables high-throughput, single-cell profiling of both RNA and cell-surface glycan expression. Using Glycomic-seq, we profiled two isogenic colorectal cancer cell lines. The results revealed various glycans associated with cancer stem cells and metastasis, demonstrating the power of integrating glycomic information with multi-omic efforts to discover biomarkers and therapeutic targets.

Polysaccharides

Viral hijacking of hnRNPH1 unveils a G-quadruplex-driven mechanism of stress control.

Viral genomes are enriched with G-quadruplexes (G4s), non-canonical structures formed in DNA or RNA upon assembly of four guanine stretches into stacked quartets. Because of their critical roles, G4s are potential antiviral targets, yet their function remains largely unknown. Here, we characterize the formation and functions of a conserved G4 within the polymerase coding region of orthoflaviviruses of the Flaviviridae family. Using yellow fever virus, we determine that this G4 promotes viral replication and suppresses host stress responses via interactions with hnRNPH1, a host nuclear protein involved in RNA processing. G4 binding to hnRNPH1 causes its cytoplasmic retention with subsequent impacts on G4-containing tRNA fragments (tiRNAs) involved in stress-mediated reductions in translation. As a result, these host stress responses and associated antiviral effects are impaired. These data reveal that the interplay between hnRNPH1 and both host and viral G4 targets controls the integrated stress response and viral replication.

Animals

Patterns of X-linked inheritance: A new approach for the genome era.

PURPOSE: The concepts of X-linked (XL) dominant and recessive inheritance originated long before dosage compensation for X chromosome genes was understood, but now have no scientific basis. However, misunderstanding of the underlying biology persists, prompting our reassessment of XL inheritance. METHODS: We reviewed data on penetrance, expressivity, and X chromosome inactivation (XCI) for 55 XL genes and 57 XL disorders, and examined variations in inheritance based on disease severity, XCI status, cell selection, and other factors. RESULTS: Our analysis demonstrated widely varying penetrance among heterozygous females that was related to severity of the phenotype particularly in males, the degree of cell selection shown by XCI patterns, cell autonomous or non-cell autonomous function of the gene product, and rare cellular interference. CONCLUSION: The conventional classification of XL inheritance into dominant and recessive subtypes is biologically flawed and should be retired. A more nuanced framework for understanding XL disorders is needed that accounts for the underlying biological complexity, and we propose 4 new groups of XL disorders with different patterns that should improve genetic diagnosis and counseling in families with XL disorders.

Humans

Implementing secondary findings analysis in a genetic and environmental research study.

PURPOSE: Optimizing return of secondary findings (SFs) in research settings requires an understanding of the complexities and challenges. METHODS: Genome sequence was generated for 4737 participants in a genetic and environmental health study, and 4630 of them consented to SF return. Variants in the American College of Medical Genetics and Genomics v3.0 genes were classified using the American College of Medical Genetics and Genomics/Association for Molecular Pathology criteria with ClinGen-approved modifications. RESULTS: Eighty-six variants were eligible for return to 102 participants. Average time to initial recontact attempt was 5.8 years. Recontact attempts reached 95 of 102 individuals. Results were returned to 57 participants. The remainder passively declined (25), actively declined (11), were lost to follow-up (5), were deceased (3), or had prior knowledge of the result (1). Return of results was positively associated with education status (2 × 3 C2, P = .0035). CONCLUSION: The interest in receiving SFs was high at the time of consenting, but a clinically validated result was returned to just over half of the individuals with an SF. Approximately 1 in 3 participants with an SF who had consented to receive them subsequently actively or passively declined receipt of the result. Given the health importance of return of SF, minimizing the time from consent to results return and tailoring outreach to education level may optimize uptake of SF return.

Adult

Tandem splice acceptor sites: Profiling their relevance to human disease.

PURPOSE: Interpretation of variation, particularly the creation or disruption of tandem splice acceptor sites (NAGNnAG variants), challenges genomic medicine practice. METHODS: We analyzed the creation and disruption of dinucleotide AG sites within ±30 bases of natural splice-acceptor sites in the GRCh37 human reference genome. These results were compared with variant data from the ClinVar and gnomAD databases, as well as with data from 779 National Institutes of Health Undiagnosed Diseases Program study participants. Using RNA sequencing, we assessed the splicing at NAGNnAG variants for 107 of the Undiagnosed Diseases Program participants and compared the empirical data with SpliceAI predictions. RESULTS: Creation or disruption of NAGNnAG sites within 30 bases of the natural splice acceptor are enriched in ClinVar compared with gnomAD; however, such variants in the 2 databases are rarely differentiated by SpliceAI scores. Empirical evaluation via RNA sequencing analysis supported novel acceptor site usage from -21 to +30; splice-altering variants did not predominate in a specific region or have SpliceAI scores invariantly, suggesting increased spliceogenicity. CONCLUSION: NAGNnAG variants within 30 bp of the natural splice acceptor have a high probability of clinical relevance and are poorly contextualized for clinical utility. Their interpretation benefits from empirical evaluation via RNA analysis.

Humans

The ClinGen Severe Combined Immunodeficiency Disease Variant Curation Expert Panel: Specifications for classification of variants in ADA, DCLRE1C, IL2RG, IL7R, JAK3, RAG1, and RAG2.

PURPOSE: This collaborative study, led by the Clinical Genome Resource Severe Combined Immunodeficiency Disease Variant Curation Expert Panel (ClinGen SCID-VCEP), implemented and adapted the American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines for interpreting germline variants in genes with established relationships to SCID. The effort focused on the 7 most common SCID-related genes identified by SCID newborn screening in North America: ADA, DCLRE1C, IL2RG, IL7R, JAK3, RAG1, and RAG2. METHODS: The SCID-VCEP conducted a rigorous review of variants that involved database analyses, literature review, and expert feedback to derive gene-specific modifications to the ACMG/AMP guidelines. These specifications were validated using a pilot set of 90 variants. RESULTS: Of these 90 variants, 25 were classified as pathogenic, 21 as likely pathogenic, 14 as variants of uncertain significance, 18 as likely benign, and 12 as benign. Seventeen variants with conflicting classifications in ClinVar were successfully resolved. The criteria included modifications to 20 of the 28 original ACMG/AMP criteria specific to SCID-related genes. CONCLUSION: The SCID-specific variant curation guidelines developed by the SCID-VCEP will enhance the precision of SCID genetic diagnosis and provide a robust framework for interpreting variants in SCID-related genes, contributing to appropriate treatment of SCID.

Humans

De novo rare EMX2 variants lead to idiopathic hypogonadotropic hypogonadism.

PURPOSE: The genetic etiology of infertility remains unknown. To identify genes for human infertility, we applied a de novo variant analysis in 142 parent-proband trios with idiopathic hypogonadotropic hypogonadism (IHH), an infertility disorder caused by gonadotropin-releasing hormone (GnRH) deficiency. METHODS: Rare de novo copy-number and single-nucleotide variants (CNVs and SNVs) were called from exome sequencing data of the IHH trios. An association study of common EMX2 variants and disease outcomes was performed in the Massachusetts General Brigham Biobank (N = 65,253). GnRH neuronal development and migration was studied in organotypic explants with knocked down of Emx2 and in a mouse model lacking Emx2. RESULTS: We identified that the gene EMX2 harbored both rare de novo CNVs and SNVs. Rare de novo EMX2 variants led to IHH, developmental delay, and hearing loss. Common EMX2 variants were linked to infertility, Parkinson disease, and hearing loss. Knockdown of Emx2 in nasal explants resulted in attenuated GnRH cell migration and GnRH cells were confined to nasal regions of Emx2 knockout (KO) mice, consistent with IHH pathogenesis. CONCLUSION: By utilizing a de novo variant analysis and cellular assays, EMX2 was uncovered as a gene for human infertility.

Humans

A proteomics-based survey reveals thrombospondin-4 as a ligand regulated by the mannose receptor in the injured lung.

Receptor-mediated cellular uptake of specific ligands constitutes an important step in the dynamic regulation of individual protein levels in extracellular fluids. With a focus on the inflammatory lung, we here performed a proteomics-based search for novel ligands regulated by the mannose receptor (MR), a macrophage-expressed endocytic receptor. WT and MR-deficient mice were exposed to lipopolysaccharide, after which the protein content in their lung epithelial lining fluid was compared by tandem mass tag-based mass spectrometry. More than 1200 proteins were identified in the epithelial lining fluid using this unbiased approach, but only six showed a statistically different abundance. Among these, an unexpected potential new ligand, thrombospondin-4 (TSP-4), displayed a striking 17-fold increased abundance in the MR-deficient mice. Experiments using exogenous addition of TSP-4 to MR-transfected CHO cells or MR-positive alveolar macrophages confirmed that TSP-4 is a ligand for MR-dependent endocytosis. Similar studies revealed that the molecular interaction with TSP-4 depends on both the lectin activity and the fibronectin type-II domain of MR and that a closely related member of the TSP family, TSP-5, is also efficiently internalized by the receptor. This was unlike the other members of this protein family, including TSPs -1 and -2, which are ligands for a close MR homologue known as urokinase plasminogen activator receptor-associated protein. Our study shows that MR takes part in the regulation of TSP-4, an important inflammatory component in the injured lung, and that two closely related endocytic receptors, expressed on different cell types, undertake the selective endocytosis of distinct members of the TSP family.

Animals

The common murine retroviral integration site activating Hhex marks a distal regulatory enhancer co-opted in human early T-cell precursor leukemia.

The Hhex gene encodes a transcription factor that is important for both embryonic and post-natal development, especially of hematopoietic tissues. Hhex is one of the most common sites of retroviral integration in mouse models. We found the most common integrations in AKXD (recombinant inbred strains) T-ALLs occur 57-61kb 3' of Hhex and activate Hhex gene expression. The genomic region of murine leukemia virus (MLV) integrations has features of a developmental stage-specific cis regulatory element (CRE), as evidenced by ATAC-seq in murine progenitor cells and high H3K27 acetylation at the syntenic CRE in human hematopoietic cell lines. With ChIP-exonuclease, we describe occupancy of LIM domain binding protein 1 (LDB1), the constitutive partner of the LIM Only-2 (LMO2), GATA1, and TAL1 transcription factors at GATA sites and at a composite GATA-E box within the CRE. With virtual 4C analysis, we observed looping between this +65kb CRE and the proximal intron one enhancer of HHEX in primary human ETP-ALLs and in normal progenitor cells. Our results show that retroviral integrations at intergenic sites can mark and take advantage of CREs. Specifically, in the case of HHEX activation, this newly described +65kb CRE is co-opted in the pathogenesis of ETP-ALL by the LMO2/LDB1 complex.

Humans

Direct anabolic metabolism of three-carbon propionate to a six-carbon metabolite occurs in vivo across tissues and species.

Anabolic metabolism of carbon in mammals is mediated via the one- and two-carbon carriers S-adenosyl methionine and acetyl-coenzyme A. In contrast, anabolic metabolism of three-carbon units via propionate has not been shown to extensively occur. Mammals are primarily thought to oxidize the three-carbon short chain fatty acid propionate by shunting propionyl-CoA to succinyl-CoA for entry into the TCA cycle. Here, we found that this may not be absolute as, in mammals, one nonoxidative fate of propionyl-CoA is to condense to two three-carbon units into a six-carbon trans-2-methyl-2-pentenoyl-CoA (2M2PE-CoA). We confirmed this reaction pathway using purified protein extracts provided limited substrates and verified the product via LC-MS using a synthetic standard. In whole-body in vivo stable isotope tracing following infusion of 13C-labeled valine at steady state, 2M2PE-CoA was found to form via propionyl-CoA in multiple murine tissues, including heart, kidney, and to a lesser degree, in brown adipose tissue, liver, and tibialis anterior muscle. Using ex vivo isotope tracing, we found that 2M2PE-CoA also formed in human myocardial tissue incubated with propionate to a limited extent. While the complete enzymology of this pathway remains to be elucidated, these results confirm the in vivo existence of at least one anabolic three- to six-carbon reaction conserved in humans and mice that utilizes propionate.

Acetyl Coenzyme A