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1.
Annu Rev Cell Dev Biol ; 37: 199-232, 2021 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-34228506

RESUMO

Nuclei are central hubs for information processing in eukaryotic cells. The need to fit large genomes into small nuclei imposes severe restrictions on genome organization and the mechanisms that drive genome-wide regulatory processes. How a disordered polymer such as chromatin, which has vast heterogeneity in its DNA and histone modification profiles, folds into discernibly consistent patterns is a fundamental question in biology. Outstanding questions include how genomes are spatially and temporally organized to regulate cellular processes with high precision and whether genome organization is causally linked to transcription regulation. The advent of next-generation sequencing, super-resolution imaging, multiplexed fluorescent in situ hybridization, and single-molecule imaging in individual living cells has caused a resurgence in efforts to understand the spatiotemporal organization of the genome. In this review, we discuss structural and mechanistic properties of genome organization at different length scales and examine changes in higher-order chromatin organization during important developmental transitions.


Assuntos
Cromatina , Cromossomos , Cromatina/genética , DNA , Genoma , Hibridização in Situ Fluorescente
2.
Cell ; 158(3): 534-48, 2014 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-25018104

RESUMO

Depending on endoplasmic reticulum (ER) stress levels, the ER transmembrane multidomain protein IRE1α promotes either adaptation or apoptosis. Unfolded ER proteins cause IRE1α lumenal domain homo-oligomerization, inducing trans autophosphorylation that further drives homo-oligomerization of its cytosolic kinase/endoribonuclease (RNase) domains to activate mRNA splicing of adaptive XBP1 transcription factor. However, under high/chronic ER stress, IRE1α surpasses an oligomerization threshold that expands RNase substrate repertoire to many ER-localized mRNAs, leading to apoptosis. To modulate these effects, we developed ATP-competitive IRE1α Kinase-Inhibiting RNase Attenuators-KIRAs-that allosterically inhibit IRE1α's RNase by breaking oligomers. One optimized KIRA, KIRA6, inhibits IRE1α in vivo and promotes cell survival under ER stress. Intravitreally, KIRA6 preserves photoreceptor functional viability in rat models of ER stress-induced retinal degeneration. Systemically, KIRA6 preserves pancreatic ß cells, increases insulin, and reduces hyperglycemia in Akita diabetic mice. Thus, IRE1α powerfully controls cell fate but can itself be controlled with small molecules to reduce cell degeneration.


Assuntos
Estresse do Retículo Endoplasmático , Endorribonucleases/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Regulação Alostérica , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular , Endorribonucleases/química , Endorribonucleases/metabolismo , Ativação Enzimática/efeitos dos fármacos , Humanos , Ilhotas Pancreáticas/metabolismo , Masculino , Camundongos , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/metabolismo , Ratos , Retina/metabolismo , Ribonucleases/antagonistas & inibidores
3.
N Engl J Med ; 390(20): 1873-1884, 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38810185

RESUMO

BACKGROUND: Autoimmune polyendocrine syndrome type 1 (APS-1) is a life-threatening, autosomal recessive syndrome caused by autoimmune regulator (AIRE) deficiency. In APS-1, self-reactive T cells escape thymic negative selection, infiltrate organs, and drive autoimmune injury. The effector mechanisms governing T-cell-mediated damage in APS-1 remain poorly understood. METHODS: We examined whether APS-1 could be classified as a disease mediated by interferon-γ. We first assessed patients with APS-1 who were participating in a prospective natural history study and evaluated mRNA and protein expression in blood and tissues. We then examined the pathogenic role of interferon-γ using Aire-/-Ifng-/- mice and Aire-/- mice treated with the Janus kinase (JAK) inhibitor ruxolitinib. On the basis of our findings, we used ruxolitinib to treat five patients with APS-1 and assessed clinical, immunologic, histologic, transcriptional, and autoantibody responses. RESULTS: Patients with APS-1 had enhanced interferon-γ responses in blood and in all examined autoimmunity-affected tissues. Aire-/- mice had selectively increased interferon-γ production by T cells and enhanced interferon-γ, phosphorylated signal transducer and activator of transcription 1 (pSTAT1), and CXCL9 signals in multiple organs. Ifng ablation or ruxolitinib-induced JAK-STAT blockade in Aire-/- mice normalized interferon-γ responses and averted T-cell infiltration and damage in organs. Ruxolitinib treatment of five patients with APS-1 led to decreased levels of T-cell-derived interferon-γ, normalized interferon-γ and CXCL9 levels, and remission of alopecia, oral candidiasis, nail dystrophy, gastritis, enteritis, arthritis, Sjögren's-like syndrome, urticaria, and thyroiditis. No serious adverse effects from ruxolitinib were identified in these patients. CONCLUSIONS: Our findings indicate that APS-1, which is caused by AIRE deficiency, is characterized by excessive, multiorgan interferon-γ-mediated responses. JAK inhibition with ruxolitinib in five patients showed promising results. (Funded by the National Institute of Allergy and Infectious Diseases and others.).


Assuntos
Proteína AIRE , Interferon gama , Inibidores de Janus Quinases , Poliendocrinopatias Autoimunes , Adulto , Animais , Feminino , Humanos , Masculino , Camundongos , Proteína AIRE/deficiência , Proteína AIRE/genética , Proteína AIRE/imunologia , Autoanticorpos/sangue , Autoanticorpos/imunologia , Quimiocina CXCL9/genética , Interferon gama/genética , Interferon gama/imunologia , Inibidores de Janus Quinases/uso terapêutico , Camundongos Knockout , Nitrilas/uso terapêutico , Poliendocrinopatias Autoimunes/genética , Poliendocrinopatias Autoimunes/tratamento farmacológico , Poliendocrinopatias Autoimunes/imunologia , Pirazóis/uso terapêutico , Pirazóis/farmacologia , Pirimidinas/uso terapêutico , Linfócitos T/imunologia , Fatores de Transcrição/genética , Fatores de Transcrição/imunologia , Projetos Piloto , Modelos Animais de Doenças , Criança , Adolescente , Pessoa de Meia-Idade
4.
J Infect Dis ; 2024 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-39140311

RESUMO

BACKGROUND: Chronic norovirus infection (CNI) causes significant morbidity in immunocompromised patients. No effective prevention or treatment currently exists. METHODS: Two patients with inborn errors of immunity, X- linked severe combined immunodeficiency (X-SCID) and DOCK8 deficiency, were followed longitudinally for clinical course, immune reconstitution, norovirus-specific T cell (NST) response, B cell reconstitution, and norovirus-specific antibody production. Samples were obtained in the peri-hematopoietic stem cell transplant setting (HSCT) before and after CNI clearance. The norovirus strain causing CNI was followed longitudinally for norovirus stool viral loads and sequencing. RESULTS: The noroviruses were identified as GII.4 Sydney[P4 New Orleans] in one patient and GII.17[P17] in the other. An exacerbation of diarrhea post-HSCT in the patient with X-SCID was consistent with norovirus infection but not with graft-vs-host-disease on pathologic samples. Both patients recovered polyfunctional NSTs in the CD4 and CD8 T cell compartments which recognized multiple norovirus structural and non-structural viral antigens. T cell responses were minimal during active CNI but detectable after resolution. Mapping of norovirus-specific T cell responses between the patient with DOCK8 and his matched sibling donor were nearly identical. B cell reconstitution or new endogenous antibody production for IgA or IgG were not observed. CONCLUSION: This report is the first to demonstrate reconstitution of norovirus-specific T cell immunity after HSCT closely temporally aligned with clearance of CNI suggesting that cellular immunity is sufficient for norovirus clearance.

5.
Genome Res ; 31(7): 1187-1202, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34168009

RESUMO

DNA topology and alternative DNA structures are implicated in regulating diverse biological processes. Although biomechanical properties of these structures have been studied extensively in vitro, characterization in vivo, particularly in multicellular organisms, is limited. We devised new methods to map DNA supercoiling and single-stranded DNA in Caenorhabditis elegans embryos and diapause larvae. To map supercoiling, we quantified the incorporation of biotinylated psoralen into DNA using high-throughput sequencing. To map single-stranded DNA, we combined permanganate treatment with genome-wide sequencing of induced double-stranded breaks. We found high levels of negative supercoiling at transcription start sites (TSSs) in embryos. GC-rich regions flanked by a sharp GC-to-AT transition delineate boundaries of supercoil propagation. In contrast to TSSs in embryos, TSSs in diapause larvae showed dramatic reductions in negative supercoiling without concomitant attenuation of transcription, suggesting developmental-stage-specific regulation. To assess whether alternative DNA structures control chromosome architecture and gene expression, we examined DNA supercoiling in the context of X-Chromosome dosage compensation. We showed that the condensin dosage compensation complex creates negative supercoils locally at its highest-occupancy binding sites but found no evidence for large-scale supercoiling domains along X Chromosomes. In contrast to transcription-coupled negative supercoiling, single-strandedness, which is most pronounced at transcript end sites, is dependent on high AT content and symmetrically positioned nucleosomes. We propose that sharp transitions in sequence composition at functional genomic elements constitute a common regulatory code and that DNA structure and propagation of torsional stress at regulatory elements are critical parameters in shaping important developmental events.

6.
Nucleic Acids Res ; 50(D1): D665-D677, 2022 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-34791429

RESUMO

The Natural Products Magnetic Resonance Database (NP-MRD) is a comprehensive, freely available electronic resource for the deposition, distribution, searching and retrieval of nuclear magnetic resonance (NMR) data on natural products, metabolites and other biologically derived chemicals. NMR spectroscopy has long been viewed as the 'gold standard' for the structure determination of novel natural products and novel metabolites. NMR is also widely used in natural product dereplication and the characterization of biofluid mixtures (metabolomics). All of these NMR applications require large collections of high quality, well-annotated, referential NMR spectra of pure compounds. Unfortunately, referential NMR spectral collections for natural products are quite limited. It is because of the critical need for dedicated, open access natural product NMR resources that the NP-MRD was funded by the National Institute of Health (NIH). Since its launch in 2020, the NP-MRD has grown quickly to become the world's largest repository for NMR data on natural products and other biological substances. It currently contains both structural and NMR data for nearly 41,000 natural product compounds from >7400 different living species. All structural, spectroscopic and descriptive data in the NP-MRD is interactively viewable, searchable and fully downloadable in multiple formats. Extensive hyperlinks to other databases of relevance are also provided. The NP-MRD also supports community deposition of NMR assignments and NMR spectra (1D and 2D) of natural products and related meta-data. The deposition system performs extensive data enrichment, automated data format conversion and spectral/assignment evaluation. Details of these database features, how they are implemented and plans for future upgrades are also provided. The NP-MRD is available at https://np-mrd.org.


Assuntos
Produtos Biológicos/química , Bases de Dados Factuais , Espectroscopia de Ressonância Magnética , Software , Produtos Biológicos/classificação , Internet
7.
Blood ; 138(12): 1019-1033, 2021 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-33876203

RESUMO

Sterile alpha motif (SAM) and Src homology-3 (SH3) domain-containing 3 (SASH3), also called SH3-containing lymphocyte protein (SLY1), is a putative adaptor protein that is postulated to play an important role in the organization of signaling complexes and propagation of signal transduction cascades in lymphocytes. The SASH3 gene is located on the X-chromosome. Here, we identified 3 novel SASH3 deleterious variants in 4 unrelated male patients with a history of combined immunodeficiency and immune dysregulation that manifested as recurrent sinopulmonary, cutaneous, and mucosal infections and refractory autoimmune cytopenias. Patients exhibited CD4+ T-cell lymphopenia, decreased T-cell proliferation, cell cycle progression, and increased T-cell apoptosis in response to mitogens. In vitro T-cell differentiation of CD34+ cells and molecular signatures of rearrangements at the T-cell receptor α (TRA) locus were indicative of impaired thymocyte survival. These patients also manifested neutropenia and B-cell and natural killer (NK)-cell lymphopenia. Lentivirus-mediated transfer of the SASH3 complementary DNA-corrected protein expression, in vitro proliferation, and signaling in SASH3-deficient Jurkat and patient-derived T cells. These findings define a new type of X-linked combined immunodeficiency in humans that recapitulates many of the abnormalities reported in mice with Sly1-/- and Sly1Δ/Δ mutations, highlighting an important role of SASH3 in human lymphocyte function and survival.


Assuntos
Cromossomos Humanos X/genética , Mutação , Doenças por Imunodeficiência Combinada Ligada ao Cromossomo X/genética , Animais , Linfócitos B/imunologia , Linfócitos T CD4-Positivos/imunologia , Pré-Escolar , Cromossomos Humanos X/imunologia , Loci Gênicos , Humanos , Células Jurkat , Células Matadoras Naturais/imunologia , Linfopenia/genética , Linfopenia/imunologia , Masculino , Camundongos , Camundongos Knockout , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Doenças por Imunodeficiência Combinada Ligada ao Cromossomo X/imunologia
8.
Nat Chem Biol ; 17(11): 1148-1156, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34556859

RESUMO

The unfolded protein response (UPR) homeostatically matches endoplasmic reticulum (ER) protein-folding capacity to cellular secretory needs. However, under high or chronic ER stress, the UPR triggers apoptosis. This cell fate dichotomy is promoted by differential activation of the ER transmembrane kinase/endoribonuclease (RNase) IRE1α. We previously found that the RNase of IRE1α can be either fully activated or inactivated by ATP-competitive kinase inhibitors. Here we developed kinase inhibitors, partial antagonists of IRE1α RNase (PAIRs), that partially antagonize the IRE1α RNase at full occupancy. Biochemical and structural studies show that PAIRs promote partial RNase antagonism by intermediately displacing the helix αC in the IRE1α kinase domain. In insulin-producing ß-cells, PAIRs permit adaptive splicing of Xbp1 mRNA while quelling destructive ER mRNA endonucleolytic decay and apoptosis. By preserving Xbp1 mRNA splicing, PAIRs allow B cells to differentiate into immunoglobulin-producing plasma cells. Thus, an intermediate RNase-inhibitory 'sweet spot', achieved by PAIR-bound IRE1α, captures a desirable conformation for drugging this master UPR sensor/effector.


Assuntos
Trifosfato de Adenosina/farmacologia , Endorribonucleases/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Trifosfato de Adenosina/química , Endorribonucleases/metabolismo , Humanos , Modelos Moleculares , Estrutura Molecular , Inibidores de Proteínas Quinases/química , Proteínas Serina-Treonina Quinases/metabolismo , Desdobramento de Proteína/efeitos dos fármacos
9.
Nat Chem Biol ; 17(5): 540-548, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33603247

RESUMO

Precision tools for spatiotemporal control of cytoskeletal motor function are needed to dissect fundamental biological processes ranging from intracellular transport to cell migration and division. Direct optical control of motor speed and direction is one promising approach, but it remains a challenge to engineer controllable motors with desirable properties such as the speed and processivity required for transport applications in living cells. Here, we develop engineered myosin motors that combine large optical modulation depths with high velocities, and create processive myosin motors with optically controllable directionality. We characterize the performance of the motors using in vitro motility assays, single-molecule tracking and live-cell imaging. Bidirectional processive motors move efficiently toward the tips of cellular protrusions in the presence of blue light, and can transport molecular cargo in cells. Robust gearshifting myosins will further enable programmable transport in contexts ranging from in vitro active matter reconstitutions to microfabricated systems that harness molecular propulsion.


Assuntos
Actinina/química , Células Epiteliais/metabolismo , Miosinas/química , Neurônios/metabolismo , Engenharia de Proteínas/métodos , Espectrina/química , Actinina/genética , Actinina/metabolismo , Animais , Avena , Linhagem Celular , Chara , Galinhas , Clonagem Molecular , Dictyostelium , Células Epiteliais/citologia , Células Epiteliais/efeitos da radiação , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Hipocampo/citologia , Hipocampo/metabolismo , Humanos , Luz , Modelos Moleculares , Movimento (Física) , Miosinas/genética , Miosinas/metabolismo , Neurônios/citologia , Neurônios/efeitos da radiação , Óptica e Fotônica/métodos , Cultura Primária de Células , Ratos , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Espectrina/genética , Espectrina/metabolismo , Nicotiana
10.
J Allergy Clin Immunol ; 150(6): 1556-1562, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35987349

RESUMO

BACKGROUND: Newborn screening can identify neonatal T-cell lymphopenia through detection of a low number of copies of T-cell receptor excision circles in dried blood spots collected at birth. After a positive screening result, further diagnostic testing is required to determine whether the subject has severe combined immunodeficiency or other causes of T-cell lymphopenia. Even after thorough evaluation, approximately 15% of children with a positive result of newborn screening for T-cell receptor excision circles remain genetically undiagnosed. Identifying the underlying genetic etiology is necessary to guide subsequent clinical management and family planning. OBJECTIVE: We sought to elucidate the genetic basis of patients with T-cell lymphopenia without an apparent genetic diagnosis. METHODS: We used clinical genomic testing as well as functional and immunologic assays to identify and elucidate the genetic and mechanistic basis of T-cell lymphopenia. RESULTS: We report 2 unrelated individuals with nonsevere T-cell lymphopenia and abnormal T-cell receptor excision circles who harbor heterozygous loss-of-function variants in forkhead box I3 transcription factor (FOXI3). CONCLUSION: Our findings support the notion that haploinsufficiency of FOXI3 results in T-cell lymphopenia with variable expressivity and that FOXI3 may be a key modulator of thymus development.


Assuntos
Genômica , Receptores de Antígenos de Linfócitos T , Recém-Nascido , Criança , Humanos , Receptores de Antígenos de Linfócitos T/genética , Linfócitos T
11.
J Allergy Clin Immunol ; 150(4): 947-954, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35753512

RESUMO

BACKGROUND: Prospective genetic evaluation of patients at this referral research hospital presents clinical research challenges. OBJECTIVES: This study sought not only a single-gene explanation for participants' immune-related presentations, but viewed each participant holistically, with the potential to have multiple genetic contributions to their immune phenotype and other heritable comorbidities relevant to their presentation and health. METHODS: This study developed a program integrating exome sequencing, chromosomal microarray, phenotyping, results return with genetic counseling, and reanalysis in 1505 individuals from 1000 families with suspected or known inborn errors of immunity. RESULTS: Probands were 50.8% female, 71.5% were ≥18 years, and had diverse immune presentations. Overall, 327 of 1000 probands (32.7%) received 361 molecular diagnoses. These included 17 probands with diagnostic copy number variants, 32 probands with secondary findings, and 31 probands with multiple molecular diagnoses. Reanalysis added 22 molecular diagnoses, predominantly due to new disease-gene associations (9 of 22, 40.9%). One-quarter of the molecular diagnoses (92 of 361) did not involve immune-associated genes. Molecular diagnosis was correlated with younger age, male sex, and a higher number of organ systems involved. This program also facilitated the discovery of new gene-disease associations such as SASH3-related immunodeficiency. A review of treatment options and ClinGen actionability curations suggest that at least 251 of 361 of these molecular diagnoses (69.5%) could translate into ≥1 management option. CONCLUSIONS: This program contributes to our understanding of the diagnostic and clinical utility whole exome analysis on a large scale.


Assuntos
Exoma , Testes Genéticos , Exoma/genética , Feminino , Testes Genéticos/métodos , Genômica , Humanos , Masculino , Fenótipo , Estudos Prospectivos
12.
Bioinformatics ; 37(13): 1884-1890, 2021 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-33471061

RESUMO

MOTIVATION: Automatic phenotype concept recognition from unstructured text remains a challenging task in biomedical text mining research. Previous works that address the task typically use dictionary-based matching methods, which can achieve high precision but suffer from lower recall. Recently, machine learning-based methods have been proposed to identify biomedical concepts, which can recognize more unseen concept synonyms by automatic feature learning. However, most methods require large corpora of manually annotated data for model training, which is difficult to obtain due to the high cost of human annotation. RESULTS: In this article, we propose PhenoTagger, a hybrid method that combines both dictionary and machine learning-based methods to recognize Human Phenotype Ontology (HPO) concepts in unstructured biomedical text. We first use all concepts and synonyms in HPO to construct a dictionary, which is then used to automatically build a distantly supervised training dataset for machine learning. Next, a cutting-edge deep learning model is trained to classify each candidate phrase (n-gram from input sentence) into a corresponding concept label. Finally, the dictionary and machine learning-based prediction results are combined for improved performance. Our method is validated with two HPO corpora, and the results show that PhenoTagger compares favorably to previous methods. In addition, to demonstrate the generalizability of our method, we retrained PhenoTagger using the disease ontology MEDIC for disease concept recognition to investigate the effect of training on different ontologies. Experimental results on the NCBI disease corpus show that PhenoTagger without requiring manually annotated training data achieves competitive performance as compared with state-of-the-art supervised methods. AVAILABILITYAND IMPLEMENTATION: The source code, API information and data for PhenoTagger are freely available at https://github.com/ncbi-nlp/PhenoTagger. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

13.
J Biomed Inform ; 129: 104059, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35351638

RESUMO

The study aims at developing a neural network model to improve the performance of Human Phenotype Ontology (HPO) concept recognition tools. We used the terms, definitions, and comments about the phenotypic concepts in the HPO database to train our model. The document to be analyzed is first split into sentences and annotated with a base method to generate candidate concepts. The sentences, along with the candidate concepts, are then fed into the pre-trained model for re-ranking. Our model comprises the pre-trained BlueBERT and a feature selection module, followed by a contrastive loss. We re-ranked the results generated by three robust HPO annotation tools and compared the performance against most of the existing approaches. The experimental results show that our model can improve the performance of the existing methods. Significantly, it boosted 3.0% and 5.6% in F1 score on the two evaluated datasets compared with the base methods. It removed more than 80% of the false positives predicted by the base methods, resulting in up to 18% improvement in precision. Our model utilizes the descriptive data in the ontology and the contextual information in the sentences for re-ranking. The results indicate that the additional information and the re-ranking model can significantly enhance the precision of HPO concept recognition compared with the base method.


Assuntos
Idioma , Redes Neurais de Computação , Bases de Dados Factuais , Humanos , Fenótipo
14.
Nat Chem Biol ; 15(4): 401-409, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30858596

RESUMO

We describe three optical tags, ArrayG, ArrayD and ArrayG/N, for intracellular tracking of single molecules over milliseconds to hours. ArrayG is a fluorogenic tag composed of a green fluorescent protein-nanobody array and monomeric wild-type green fluorescent protein binders that are initially dim but brighten ~26-fold on binding with the array. By balancing the rates of binder production, photobleaching and stochastic binder exchange, we achieve temporally unlimited tracking of single molecules. High-speed tracking of ArrayG-tagged kinesins and integrins for thousands of frames reveals novel dynamical features. Tracking of single histones at 0.5 Hz for >1 hour with the import competent ArrayG/N tag shows that chromosomal loci behave as Rouse polymers with visco-elastic memory and exhibit a non-Gaussian displacement distribution. ArrayD, based on a dihydrofolate reductase nanobody array and dihydrofolate reductase-fluorophore binder, enables dual-color imaging. The arrays combine brightness, fluorogenicity, fluorescence replenishment and extended fluorophore choice, opening new avenues for tracking single molecules in living cells.


Assuntos
Corantes Fluorescentes/química , Microscopia de Fluorescência/métodos , Imagem Individual de Molécula/métodos , Linhagem Celular , Cor , Corantes Fluorescentes/síntese química , Proteínas de Fluorescência Verde , Células HeLa , Humanos , Anticorpos de Domínio Único
15.
PLoS Comput Biol ; 16(9): e1008193, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32925919

RESUMO

Segmenting cell nuclei within microscopy images is a ubiquitous task in biological research and clinical applications. Unfortunately, segmenting low-contrast overlapping objects that may be tightly packed is a major bottleneck in standard deep learning-based models. We report a Nuclear Segmentation Tool (NuSeT) based on deep learning that accurately segments nuclei across multiple types of fluorescence imaging data. Using a hybrid network consisting of U-Net and Region Proposal Networks (RPN), followed by a watershed step, we have achieved superior performance in detecting and delineating nuclear boundaries in 2D and 3D images of varying complexities. By using foreground normalization and additional training on synthetic images containing non-cellular artifacts, NuSeT improves nuclear detection and reduces false positives. NuSeT addresses common challenges in nuclear segmentation such as variability in nuclear signal and shape, limited training sample size, and sample preparation artifacts. Compared to other segmentation models, NuSeT consistently fares better in generating accurate segmentation masks and assigning boundaries for touching nuclei.


Assuntos
Núcleo Celular/fisiologia , Aprendizado Profundo , Processamento de Imagem Assistida por Computador/métodos , Microscopia/métodos , Algoritmos , Artefatos , Biologia Computacional , Células HeLa , Humanos , Software
16.
Environ Monit Assess ; 193(10): 652, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34528153

RESUMO

The increasing use of gibberellic acid (GA3) to promote fruit growth and yield has necessitated research into its trace level determination and estimation in harvested product. The phytohormone has increased the tomato yield (tonne ha-1) up to 24.7% with uniform fruit shape, size colour and lustre. A fast, simple, high-throughput analytical method was standardised based on electrospray ionisation - liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were extracted using acidified (1% formic acid) methanol. The method was validated as per the SANTE/12682/2019 guidelines. The limits of detection (LOD) and quantification (LOQ) were 0.01 and 0.05 mg kg-1. The average recoveries at LOQ and higher levels were in the range of 86-108% with relative standard deviation (RSD) < 20%. The validated method was successfully applied under field condition by following first-order kinetics with half-lives (T1/2) 1.76 days (recommended dose) and 1.99 days (double dose). The estimated pre-harvest intervals (PHIs) were 6 days (recommended dose) and 8 days (double dose). Studies on dietary risk assessment concluded that even after spray of GA3 at recommended dose, the harvested produce (tomato) could be consumed safely.


Assuntos
Solanum lycopersicum , Espectrometria de Massas em Tandem , Cromatografia Líquida , Monitoramento Ambiental , Giberelinas , Medição de Risco
17.
Am J Hum Genet ; 100(6): 895-906, 2017 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-28552198

RESUMO

With advances in genomic sequencing technology, the number of reported gene-disease relationships has rapidly expanded. However, the evidence supporting these claims varies widely, confounding accurate evaluation of genomic variation in a clinical setting. Despite the critical need to differentiate clinically valid relationships from less well-substantiated relationships, standard guidelines for such evaluation do not currently exist. The NIH-funded Clinical Genome Resource (ClinGen) has developed a framework to define and evaluate the clinical validity of gene-disease pairs across a variety of Mendelian disorders. In this manuscript we describe a proposed framework to evaluate relevant genetic and experimental evidence supporting or contradicting a gene-disease relationship and the subsequent validation of this framework using a set of representative gene-disease pairs. The framework provides a semiquantitative measurement for the strength of evidence of a gene-disease relationship that correlates to a qualitative classification: "Definitive," "Strong," "Moderate," "Limited," "No Reported Evidence," or "Conflicting Evidence." Within the ClinGen structure, classifications derived with this framework are reviewed and confirmed or adjusted based on clinical expertise of appropriate disease experts. Detailed guidance for utilizing this framework and access to the curation interface is available on our website. This evidence-based, systematic method to assess the strength of gene-disease relationships will facilitate more knowledgeable utilization of genomic variants in clinical and research settings.


Assuntos
Estudos de Associação Genética , Predisposição Genética para Doença , Genômica , Humanos , Reprodutibilidade dos Testes
18.
Am J Med Genet A ; 182(5): 1167-1176, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32181591

RESUMO

The majority of patients with spinal muscular atrophy (SMA) identified to date harbor a biallelic exonic deletion of SMN1. However, there have been reports of SMA-like disorders that are independent of SMN1, including those due to pathogenic variants in the glycyl-tRNA synthetase gene (GARS1). We report three unrelated patients with de novo variants in GARS1 that are associated with infantile-onset SMA (iSMA). Patients were ascertained during inpatient hospital evaluations for complications of neuropathy. Evaluations were completed as indicated for clinical care and management and informed consent for publication was obtained. One newly identified, disease-associated GARS1 variant, identified in two out of three patients, was analyzed by functional studies in yeast complementation assays. Genomic analyses by exome and/or gene panel and SMN1 copy number analysis of three patients identified two previously undescribed de novo missense variants in GARS1 and excluded SMN1 as the causative gene. Functional studies in yeast revealed that one of the de novo GARS1 variants results in a loss-of-function effect, consistent with other pathogenic GARS1 alleles. In sum, the patients' clinical presentation, assessments of previously identified GARS1 variants and functional assays in yeast suggest that the GARS1 variants described here cause iSMA. GARS1 variants have been previously associated with Charcot-Marie-Tooth disease (CMT2D) and distal SMA type V (dSMAV). Our findings expand the allelic heterogeneity of GARS-associated disease and support that severe early-onset SMA can be caused by variants in this gene. Distinguishing the SMA phenotype caused by SMN1 variants from that due to pathogenic variants in other genes such as GARS1 significantly alters approaches to treatment.


Assuntos
Predisposição Genética para Doença , Glicina-tRNA Ligase/genética , Atrofias Musculares Espinais da Infância/genética , Proteína 1 de Sobrevivência do Neurônio Motor/genética , Doença de Charcot-Marie-Tooth/genética , Doença de Charcot-Marie-Tooth/fisiopatologia , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Atrofia Muscular Espinal/genética , Atrofia Muscular Espinal/fisiopatologia , Mutação de Sentido Incorreto/genética , Fenótipo , Atrofias Musculares Espinais da Infância/diagnóstico por imagem , Atrofias Musculares Espinais da Infância/fisiopatologia
19.
J Craniofac Surg ; 31(4): e394-e397, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32176021

RESUMO

AIM: The aim of this study is to determine the frequency of pediatric pathologies and their distribution according to age, gender, site and types of lesions reported over a period of 2004 - 2019 in two prominent Dental Colleges at Western UP, India. MATERIAL AND METHODS: All the cases of pediatric pathology were retrospectively analyzed and reviewed that reported in the Department of Oral And Maxillofacial Surgery of 2 prominent dental colleges of Western UP, India. All consecutive patients (< 18 years), between 2004 to 2019, histologically diagnosed as having an intraosseous tumor or tumor-like lesions and cystic lesion, vascular lesions, patients with space infections and hardware infection formed the study population. Patients fulfilling the inclusion criteria were only considered for further study. The study was granted an exemption by the institutes. The entire study material was analyzed and grouped into prominent categories for logical conclusions: The accumulated data was grouped, entered, and analyzed. RESULTS: One hundred two cases fulfilled the criteria. Gender distribution was equal, with mandible predominance and a predominance of non-odontogenic lesions. There were 4 malignant and 57 benign conditions. There were 23 lesions in the anterior jaw and 38 lesions were present in the posterior jaw. CONCLUSION: The pattern of pediatric pathology presentation from this part of India has been documented. In this study, the pediatric jaw tumors are less common compared to those in adult jaw tumors with non-odontogenic tumors being more common.


Assuntos
Cabeça/patologia , Pescoço/patologia , Adolescente , Criança , Humanos , Incidência , Índia , Neoplasias Maxilomandibulares/patologia , Prevalência , Estudos Retrospectivos , Cirurgia Bucal
20.
Molecules ; 25(24)2020 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-33322293

RESUMO

Panax quinquefolius (North American ginseng, NAG) is a popular medicinal plant used widely in traditional medicine. NAG products are currently available in various forms such as roots, extracts, nutraceuticals, dietary supplements, energy drinks, etc. NAG polysaccharides are recognized as one of the major bioactive ingredients. However, most NAG reviews are focused on ginsenosides with little information on polysaccharides. NAG polysaccharides have demonstrated a therapeutic activity in numerous studies, in which many of the bioactivities involve regulation of the immune response. The purpose of this review is to summarize the structural features and the immunomodulatory properties of crude, partially purified, and pure polysaccharides isolated from NAG. Receptors of the innate immune system that potentially bind to NAG polysaccharides and the respective signal transduction pathways initiated by these compounds are discussed. Major challenges, recent innovations, and future directions in NAG polysaccharide research are also summarized.


Assuntos
Fatores Imunológicos/química , Imunomodulação , Panax/química , Polissacarídeos/química , Adjuvantes Imunológicos/metabolismo , Animais , Suplementos Nutricionais , Endotoxinas/química , Ginsenosídeos/metabolismo , Humanos , Imunidade Inata , Extratos Vegetais/química , Raízes de Plantas/química , Plantas Medicinais
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