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  1. Article: Alpha cell dysfunction in type 1 diabetes is independent of a senescence program.

    Brawerman, Gabriel / Ntranos, Vasilis / Thompson, Peter J

    Frontiers in endocrinology

    2022  Volume 13, Page(s) 932516

    Abstract: Type 1 Diabetes (T1D) is caused by insulin deficiency, due to progressive autoimmune destruction of pancreatic β cells. Glucagon-secreting α cells become dysfunctional in T1D and contribute to pathophysiology, however, the mechanisms involved are unclear. ...

    Abstract Type 1 Diabetes (T1D) is caused by insulin deficiency, due to progressive autoimmune destruction of pancreatic β cells. Glucagon-secreting α cells become dysfunctional in T1D and contribute to pathophysiology, however, the mechanisms involved are unclear. While the majority of β cells are destroyed in T1D, some β cells escape this fate and become senescent but whether α cell dysfunction involves a senescence program has not been explored. Here we addressed the question of whether α cells become senescent during the natural history of T1D in the non-obese diabetic (NOD) mouse model and humans. NOD mice had several distinct subpopulations of α cells, but none were defined by markers of senescence at the transcriptional or protein level. Similarly, α cells of human T1D donors did not express senescence markers. Despite the lack of senescence in α cells
    MeSH term(s) Mice ; Animals ; Humans ; Diabetes Mellitus, Type 1/metabolism ; Mice, Inbred NOD ; Glucagon/metabolism ; Glucagon-Secreting Cells/metabolism ; Insulin/metabolism ; Biomarkers/metabolism
    Chemical Substances Glucagon (9007-92-5) ; Insulin ; Biomarkers
    Language English
    Publishing date 2022-10-07
    Publishing country Switzerland
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, N.I.H., Extramural
    ZDB-ID 2592084-4
    ISSN 1664-2392
    ISSN 1664-2392
    DOI 10.3389/fendo.2022.932516
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Sox9 regulates alternative splicing and pancreatic beta cell function.

    Puri, Sapna / Maachi, Hasna / Nair, Gopika / Russ, Holger A / Chen, Richard / Pulimeno, Pamela / Cutts, Zachary / Ntranos, Vasilis / Hebrok, Matthias

    Nature communications

    2024  Volume 15, Issue 1, Page(s) 588

    Abstract: Despite significant research, mechanisms underlying the failure of islet beta cells that result in type 2 diabetes (T2D) are still under investigation. Here, we report that Sox9, a transcriptional regulator of pancreas development, also functions in ... ...

    Abstract Despite significant research, mechanisms underlying the failure of islet beta cells that result in type 2 diabetes (T2D) are still under investigation. Here, we report that Sox9, a transcriptional regulator of pancreas development, also functions in mature beta cells. Our results show that Sox9-depleted rodent beta cells have defective insulin secretion, and aging animals develop glucose intolerance, mimicking the progressive degeneration observed in T2D. Using genome editing in human stem cells, we show that beta cells lacking SOX9 have stunted first-phase insulin secretion. In human and rodent cells, loss of Sox9 disrupts alternative splicing and triggers accumulation of non-functional isoforms of genes with key roles in beta cell function. Sox9 depletion reduces expression of protein-coding splice variants of the serine-rich splicing factor arginine SRSF5, a major splicing enhancer that regulates alternative splicing. Our data highlight the role of SOX9 as a regulator of alternative splicing in mature beta cell function.
    MeSH term(s) Animals ; Humans ; Alternative Splicing/genetics ; Diabetes Mellitus, Type 2/genetics ; Diabetes Mellitus, Type 2/metabolism ; Insulin-Secreting Cells/metabolism ; Islets of Langerhans/metabolism ; RNA Splicing
    Chemical Substances SOX9 protein, human
    Language English
    Publishing date 2024-01-18
    Publishing country England
    Document type Journal Article
    ZDB-ID 2553671-0
    ISSN 2041-1723 ; 2041-1723
    ISSN (online) 2041-1723
    ISSN 2041-1723
    DOI 10.1038/s41467-023-44384-8
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Genome-wide prediction of disease variant effects with a deep protein language model.

    Brandes, Nadav / Goldman, Grant / Wang, Charlotte H / Ye, Chun Jimmie / Ntranos, Vasilis

    Nature genetics

    2023  Volume 55, Issue 9, Page(s) 1512–1522

    Abstract: Predicting the effects of coding variants is a major challenge. While recent deep-learning models have improved variant effect prediction accuracy, they cannot analyze all coding variants due to dependency on close homologs or software limitations. Here ... ...

    Abstract Predicting the effects of coding variants is a major challenge. While recent deep-learning models have improved variant effect prediction accuracy, they cannot analyze all coding variants due to dependency on close homologs or software limitations. Here we developed a workflow using ESM1b, a 650-million-parameter protein language model, to predict all ~450 million possible missense variant effects in the human genome, and made all predictions available on a web portal. ESM1b outperformed existing methods in classifying ~150,000 ClinVar/HGMD missense variants as pathogenic or benign and predicting measurements across 28 deep mutational scan datasets. We further annotated ~2 million variants as damaging only in specific protein isoforms, demonstrating the importance of considering all isoforms when predicting variant effects. Our approach also generalizes to more complex coding variants such as in-frame indels and stop-gains. Together, these results establish protein language models as an effective, accurate and general approach to predicting variant effects.
    MeSH term(s) Humans ; Computational Biology/methods ; Software ; Mutation, Missense/genetics ; Proteins/genetics ; Genome, Human/genetics
    Chemical Substances Proteins
    Language English
    Publishing date 2023-08-10
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 1108734-1
    ISSN 1546-1718 ; 1061-4036
    ISSN (online) 1546-1718
    ISSN 1061-4036
    DOI 10.1038/s41588-023-01465-0
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Determining sequencing depth in a single-cell RNA-seq experiment.

    Zhang, Martin Jinye / Ntranos, Vasilis / Tse, David

    Nature communications

    2020  Volume 11, Issue 1, Page(s) 774

    Abstract: An underlying question for virtually all single-cell RNA sequencing experiments is how to allocate the limited sequencing budget: deep sequencing of a few cells or shallow sequencing of many cells? Here we present a mathematical framework which reveals ... ...

    Abstract An underlying question for virtually all single-cell RNA sequencing experiments is how to allocate the limited sequencing budget: deep sequencing of a few cells or shallow sequencing of many cells? Here we present a mathematical framework which reveals that, for estimating many important gene properties, the optimal allocation is to sequence at a depth of around one read per cell per gene. Interestingly, the corresponding optimal estimator is not the widely-used plug-in estimator, but one developed via empirical Bayes.
    MeSH term(s) Computational Biology/methods ; Computational Biology/statistics & numerical data ; Gene Expression ; Gene Regulatory Networks ; In Situ Hybridization, Fluorescence ; Models, Theoretical ; Reproducibility of Results ; S100 Calcium-Binding Protein A4/genetics ; Sequence Analysis, RNA/methods ; Sequence Analysis, RNA/statistics & numerical data ; Single-Cell Analysis/methods ; Single-Cell Analysis/statistics & numerical data
    Chemical Substances S100 Calcium-Binding Protein A4
    Language English
    Publishing date 2020-02-07
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 2553671-0
    ISSN 2041-1723 ; 2041-1723
    ISSN (online) 2041-1723
    ISSN 2041-1723
    DOI 10.1038/s41467-020-14482-y
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Deterministic column subset selection for single-cell RNA-Seq.

    McCurdy, Shannon R / Ntranos, Vasilis / Pachter, Lior

    PloS one

    2019  Volume 14, Issue 1, Page(s) e0210571

    Abstract: Analysis of single-cell RNA sequencing (scRNA-Seq) data often involves filtering out uninteresting or poorly measured genes and dimensionality reduction to reduce noise and simplify data visualization. However, techniques such as principal components ... ...

    Abstract Analysis of single-cell RNA sequencing (scRNA-Seq) data often involves filtering out uninteresting or poorly measured genes and dimensionality reduction to reduce noise and simplify data visualization. However, techniques such as principal components analysis (PCA) fail to preserve non-negativity and sparsity structures present in the original matrices, and the coordinates of projected cells are not easily interpretable. Commonly used thresholding methods to filter genes avoid those pitfalls, but ignore collinearity and covariance in the original matrix. We show that a deterministic column subset selection (DCSS) method possesses many of the favorable properties of common thresholding methods and PCA, while avoiding pitfalls from both. We derive new spectral bounds for DCSS. We apply DCSS to two measures of gene expression from two scRNA-Seq experiments with different clustering workflows, and compare to three thresholding methods. In each case study, the clusters based on the small subset of the complete gene expression profile selected by DCSS are similar to clusters produced from the full set. The resulting clusters are informative for cell type.
    MeSH term(s) Algorithms ; Cluster Analysis ; Gene Expression Profiling/methods ; High-Throughput Nucleotide Sequencing/methods ; Principal Component Analysis ; RNA/genetics ; RNA, Small Cytoplasmic/genetics ; Sequence Analysis, RNA/methods ; Single-Cell Analysis/methods
    Chemical Substances RNA, Small Cytoplasmic ; RNA (63231-63-0)
    Language English
    Publishing date 2019-01-25
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ISSN 1932-6203
    ISSN (online) 1932-6203
    DOI 10.1371/journal.pone.0210571
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: A discriminative learning approach to differential expression analysis for single-cell RNA-seq.

    Ntranos, Vasilis / Yi, Lynn / Melsted, Páll / Pachter, Lior

    Nature methods

    2019  Volume 16, Issue 2, Page(s) 163–166

    Abstract: Single-cell RNA-seq makes it possible to characterize the transcriptomes of cell types across different conditions and to identify their transcriptional signatures via differential analysis. Our method detects changes in transcript dynamics and in ... ...

    Abstract Single-cell RNA-seq makes it possible to characterize the transcriptomes of cell types across different conditions and to identify their transcriptional signatures via differential analysis. Our method detects changes in transcript dynamics and in overall gene abundance in large numbers of cells to determine differential expression. When applied to transcript compatibility counts obtained via pseudoalignment, our approach provides a quantification-free analysis of 3' single-cell RNA-seq that can identify previously undetectable marker genes.
    MeSH term(s) Algorithms ; Computer Simulation ; Databases, Genetic ; Gene Expression Profiling ; Gene Expression Regulation ; Genetic Markers ; Humans ; Leukocytes, Mononuclear/cytology ; Protein Isoforms ; RNA/genetics ; Regression Analysis ; Sequence Analysis, RNA ; Single-Cell Analysis/instrumentation ; Single-Cell Analysis/methods ; Software ; T-Lymphocytes, Cytotoxic/cytology ; Transcriptome
    Chemical Substances Genetic Markers ; Protein Isoforms ; RNA (63231-63-0)
    Language English
    Publishing date 2019-01-21
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 2169522-2
    ISSN 1548-7105 ; 1548-7091
    ISSN (online) 1548-7105
    ISSN 1548-7091
    DOI 10.1038/s41592-018-0303-9
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: The barcode, UMI, set format and BUStools.

    Melsted, Páll / Ntranos, Vasilis / Pachter, Lior

    Bioinformatics (Oxford, England)

    2019  Volume 35, Issue 21, Page(s) 4472–4473

    Abstract: Summary: We introduce the Barcode-UMI-Set format (BUS) for representing pseudoalignments of reads from single-cell RNA-seq experiments. The format can be used with all single-cell RNA-seq technologies, and we show that BUS files can be efficiently ... ...

    Abstract Summary: We introduce the Barcode-UMI-Set format (BUS) for representing pseudoalignments of reads from single-cell RNA-seq experiments. The format can be used with all single-cell RNA-seq technologies, and we show that BUS files can be efficiently generated. BUStools is a suite of tools for working with BUS files and facilitates rapid quantification and analysis of single-cell RNA-seq data. The BUS format therefore makes possible the development of modular, technology-specific and robust workflows for single-cell RNA-seq analysis.
    Availability and implementation: http://BUStools.github.io/ and http://pachterlab.github.io/kallisto/singlecell.html.
    Supplementary information: Supplementary data are available at Bioinformatics online.
    MeSH term(s) Sequence Analysis, RNA ; Single-Cell Analysis ; Software ; Whole Exome Sequencing
    Language English
    Publishing date 2019-05-31
    Publishing country England
    Document type Journal Article
    ZDB-ID 1422668-6
    ISSN 1367-4811 ; 1367-4803
    ISSN (online) 1367-4811
    ISSN 1367-4803
    DOI 10.1093/bioinformatics/btz279
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  8. Article: Investigating the sources of variable impact of pathogenic variants in monogenic metabolic conditions.

    Wei, Angela / Border, Richard / Fu, Boyang / Cullina, Sinead / Brandes, Nadav / Jang, Seon-Kyeong / Sankararaman, Sriram / Kenny, Eimear / Udler, Mariam S / Ntranos, Vasilis / Zaitlen, Noah / Arboleda, Valerie

    medRxiv : the preprint server for health sciences

    2024  

    Abstract: Over three percent of people carry a dominant pathogenic variant, yet only a fraction of carriers develop disease. Disease phenotypes from carriers of variants in the same gene range from mild to severe. Here, we investigate underlying mechanisms for ... ...

    Abstract Over three percent of people carry a dominant pathogenic variant, yet only a fraction of carriers develop disease. Disease phenotypes from carriers of variants in the same gene range from mild to severe. Here, we investigate underlying mechanisms for this heterogeneity: variable variant effect sizes, carrier polygenic backgrounds, and modulation of carrier effect by genetic background (marginal epistasis). We leveraged exomes and clinical phenotypes from the UK Biobank and the Mt. Sinai BioMe Biobank to identify carriers of pathogenic variants affecting cardiometabolic traits. We employed recently developed methods to study these cohorts, observing strong statistical support and clinical translational potential for all three mechanisms of variable carrier penetrance and disease severity. For example, scores from our recent model of variant pathogenicity were tightly correlated with phenotype amongst clinical variant carriers, they predicted effects of variants of unknown significance, and they distinguished gain- from loss-of-function variants. We also found that polygenic scores predicted phenotypes amongst pathogenic carriers and that epistatic effects can exceed main carrier effects by an order of magnitude.
    Language English
    Publishing date 2024-05-01
    Publishing country United States
    Document type Preprint
    DOI 10.1101/2023.09.14.23295564
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Extrathymic

    Gillis-Buck, Eva / Miller, Haleigh / Sirota, Marina / Sanders, Stephan J / Ntranos, Vasilis / Anderson, Mark S / Gardner, James M / MacKenzie, Tippi C

    Science immunology

    2021  Volume 6, Issue 61

    Abstract: Healthy pregnancy requires tolerance to fetal alloantigens as well as syngeneic embryonic and placental antigens. Given the importance of the autoimmune regulator ( ...

    Abstract Healthy pregnancy requires tolerance to fetal alloantigens as well as syngeneic embryonic and placental antigens. Given the importance of the autoimmune regulator (
    MeSH term(s) Animals ; Epithelial Cells/immunology ; Female ; Fetal Growth Retardation/immunology ; Fetus/immunology ; Immune Tolerance ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Mice, Transgenic ; Placenta/immunology ; Pregnancy ; Thymus Gland/immunology ; Transcription Factors/genetics ; Transcription Factors/immunology ; AIRE Protein
    Chemical Substances Transcription Factors
    Language English
    Publishing date 2021-07-16
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ISSN 2470-9468
    ISSN (online) 2470-9468
    DOI 10.1126/sciimmunol.abf1968
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: Targeted Elimination of Senescent Beta Cells Prevents Type 1 Diabetes.

    Thompson, Peter J / Shah, Ajit / Ntranos, Vasilis / Van Gool, Frederic / Atkinson, Mark / Bhushan, Anil

    Cell metabolism

    2019  Volume 29, Issue 5, Page(s) 1045–1060.e10

    Abstract: Type 1 diabetes (T1D) is an organ-specific autoimmune disease characterized by hyperglycemia due to progressive loss of pancreatic beta cells. Immune-mediated beta cell destruction drives the disease, but whether beta cells actively participate in the ... ...

    Abstract Type 1 diabetes (T1D) is an organ-specific autoimmune disease characterized by hyperglycemia due to progressive loss of pancreatic beta cells. Immune-mediated beta cell destruction drives the disease, but whether beta cells actively participate in the pathogenesis remains unclear. Here, we show that during the natural history of T1D in humans and the non-obese diabetic (NOD) mouse model, a subset of beta cells acquires a senescence-associated secretory phenotype (SASP). Senescent beta cells upregulated pro-survival mediator Bcl-2, and treatment of NOD mice with Bcl-2 inhibitors selectively eliminated these cells without altering the abundance of the immune cell types involved in the disease. Significantly, elimination of senescent beta cells halted immune-mediated beta cell destruction and was sufficient to prevent diabetes. Our findings demonstrate that beta cell senescence is a significant component of the pathogenesis of T1D and indicate that clearance of senescent beta cells could be a new therapeutic approach for T1D.
    MeSH term(s) Adolescent ; Adult ; Aged ; Animals ; Biphenyl Compounds/pharmacology ; Bridged Bicyclo Compounds, Heterocyclic/pharmacology ; Cellular Senescence/drug effects ; Child ; Child, Preschool ; Cohort Studies ; Diabetes Mellitus, Type 1/metabolism ; Diabetes Mellitus, Type 1/prevention & control ; Female ; Fibroblasts ; Humans ; Hyperglycemia/metabolism ; Hyperglycemia/prevention & control ; Insulin-Secreting Cells/metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Inbred NOD ; Nitrophenols/pharmacology ; Piperazines/pharmacology ; Proto-Oncogene Proteins c-bcl-2/antagonists & inhibitors ; Proto-Oncogene Proteins c-bcl-2/metabolism ; Sulfonamides/pharmacology ; THP-1 Cells ; Young Adult
    Chemical Substances ABT-737 ; Biphenyl Compounds ; Bridged Bicyclo Compounds, Heterocyclic ; Nitrophenols ; Piperazines ; Proto-Oncogene Proteins c-bcl-2 ; Sulfonamides ; venetoclax (N54AIC43PW)
    Language English
    Publishing date 2019-02-21
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 2176834-1
    ISSN 1932-7420 ; 1550-4131
    ISSN (online) 1932-7420
    ISSN 1550-4131
    DOI 10.1016/j.cmet.2019.01.021
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