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1.
Cell ; 164(5): 999-1014, 2016 Feb 25.
Article in English | MEDLINE | ID: mdl-26875865

ABSTRACT

Transcription factors (TFs) are thought to function with partners to achieve specificity and precise quantitative outputs. In the developing heart, heterotypic TF interactions, such as between the T-box TF TBX5 and the homeodomain TF NKX2-5, have been proposed as a mechanism for human congenital heart defects. We report extensive and complex interdependent genomic occupancy of TBX5, NKX2-5, and the zinc finger TF GATA4 coordinately controlling cardiac gene expression, differentiation, and morphogenesis. Interdependent binding serves not only to co-regulate gene expression but also to prevent TFs from distributing to ectopic loci and activate lineage-inappropriate genes. We define preferential motif arrangements for TBX5 and NKX2-5 cooperative binding sites, supported at the atomic level by their co-crystal structure bound to DNA, revealing a direct interaction between the two factors and induced DNA bending. Complex interdependent binding mechanisms reveal tightly regulated TF genomic distribution and define a combinatorial logic for heterotypic TF regulation of differentiation.


Subject(s)
GATA4 Transcription Factor/metabolism , Homeodomain Proteins/metabolism , Myocardium/cytology , Organogenesis , T-Box Domain Proteins/metabolism , Transcription Factors/metabolism , Animals , Cell Differentiation , Crystallography, X-Ray , Embryo, Mammalian/metabolism , Homeobox Protein Nkx-2.5 , Homeodomain Proteins/genetics , Mice , Mice, Transgenic , Models, Molecular , Myocardium/metabolism , Promoter Regions, Genetic , Protein Interaction Domains and Motifs , T-Box Domain Proteins/genetics , Transcription Factors/genetics
2.
Hum Mol Genet ; 32(6): 959-970, 2023 03 06.
Article in English | MEDLINE | ID: mdl-36229919

ABSTRACT

Haploinsufficiency of TGF-beta-activated kinase 1 (MAP3K7) binding protein 2 (TAB2) has been associated with congenital heart disease and more recently multiorgan structural abnormalities. Missense variant represents a major proportion of non-synonymous TAB2 variants reported in gnomAD (295/576) and Clinvar (16/73), most of which are variants of uncertain significance (VUSs). However, interpretation of TAB2 missense variants remains challenging because of lack of functional assays. To address this issue, we established a cell-based luciferase assay that enables high-throughput screening of TAB2 variants to assess the functional consequence for predicting variant pathogenicity. Using this platform, we screened 47 TAB2 variants including five pathogenic controls and one benign control, and the results showed that the transcriptional activity of activator protein 1 (AP-1) but not nuclear factor kappa B predicts the TAB2 variant pathogenicity. This assay provides accurate functional readout for both loss-of-function (LOF) and gain-of-function variants, which are associated with distinct phenotypes. In all, 22 out of 32 tested VUSs were reclassified. Genotype-Phenotype association showed that most patients with partial LOF variants do not exhibit congenital heart disease but high frequency of developmental delay, hypotonia and dysmorphic features, which suggests that genetic testing for TAB2 is needed for a broader spectrum of patients with more diverse phenotypes. Molecular modeling with Npl4 zinc finger (NZF) domain variants revealed that the stability of the NZF domain in TAB2 protein is crucial for AP-1 activation. In conclusion, we developed a highly effective functional assay for TAB2 variant prediction and interpretation.


Subject(s)
Adaptor Proteins, Signal Transducing , Heart Defects, Congenital , Humans , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/metabolism , Transcription Factor AP-1/genetics , Transcription Factor AP-1/metabolism , Virulence , NF-kappa B/metabolism , Heart Defects, Congenital/genetics
3.
Nucleic Acids Res ; 51(14): 7184-7197, 2023 08 11.
Article in English | MEDLINE | ID: mdl-37395403

ABSTRACT

Single nucleotide mutation rates have critical implications for human evolution and genetic diseases. Importantly, the rates vary substantially across the genome and the principles underlying such variations remain poorly understood. A recent model explained much of this variation by considering higher-order nucleotide interactions in the 7-mer sequence context around mutated nucleotides. This model's success implicates a connection between DNA shape and mutation rates. DNA shape, i.e. structural properties like helical twist and tilt, is known to capture interactions between nucleotides within a local context. Thus, we hypothesized that changes in DNA shape features at and around mutated positions can explain mutation rate variations in the human genome. Indeed, DNA shape-based models of mutation rates showed similar or improved performance over current nucleotide sequence-based models. These models accurately characterized mutation hotspots in the human genome and revealed the shape features whose interactions underlie mutation rate variations. DNA shape also impacts mutation rates within putative functional regions like transcription factor binding sites where we find a strong association between DNA shape and position-specific mutation rates. This work demonstrates the structural underpinnings of nucleotide mutations in the human genome and lays the groundwork for future models of genetic variations to incorporate DNA shape.


Subject(s)
Genome, Human , Mutation Rate , Humans , Mutation , DNA/genetics , Nucleotides/genetics
4.
Bioinformatics ; 39(6)2023 06 01.
Article in English | MEDLINE | ID: mdl-37285319

ABSTRACT

MOTIVATION: Spatial transcriptomics (ST) can reveal the existence and extent of spatial variation of gene expression in complex tissues. Such analyses could help identify spatially localized processes underlying a tissue's function. Existing tools to detect spatially variable genes assume a constant noise variance across spatial locations. This assumption might miss important biological signals when the variance can change across locations. RESULTS: In this article, we propose NoVaTeST, a framework to identify genes with location-dependent noise variance in ST data. NoVaTeST models gene expression as a function of spatial location and allows the noise to vary spatially. NoVaTeST then statistically compares this model to one with constant noise and detects genes showing significant spatial noise variation. We refer to these genes as "noisy genes." In tumor samples, the noisy genes detected by NoVaTeST are largely independent of the spatially variable genes detected by existing tools that assume constant noise, and provide important biological insights into tumor microenvironments. AVAILABILITY AND IMPLEMENTATION: An implementation of the NoVaTeST framework in Python along with instructions for running the pipeline is available at https://github.com/abidabrar-bracu/NoVaTeST.


Subject(s)
Software , Transcriptome , Gene Expression Profiling
5.
Bioinformatics ; 39(10)2023 Oct 03.
Article in English | MEDLINE | ID: mdl-37756699

ABSTRACT

MOTIVATION: Spatial domain identification is a very important problem in the field of spatial transcriptomics. The state-of-the-art solutions to this problem focus on unsupervised methods, as there is lack of data for a supervised learning formulation. The results obtained from these methods highlight significant opportunities for improvement. RESULTS: In this article, we propose a potential avenue for enhancement through the development of a semi-supervised convolutional neural network based approach. Named "ScribbleDom", our method leverages human expert's input as a form of semi-supervision, thereby seamlessly combines the cognitive abilities of human experts with the computational power of machines. ScribbleDom incorporates a loss function that integrates two crucial components: similarity in gene expression profiles and adherence to the valuable input of a human annotator through scribbles on histology images, providing prior knowledge about spot labels. The spatial continuity of the tissue domains is taken into account by extracting information on the spot microenvironment through convolution filters of varying sizes, in the form of "Inception" blocks. By leveraging this semi-supervised approach, ScribbleDom significantly improves the quality of spatial domains, yielding superior results both quantitatively and qualitatively. Our experiments on several benchmark datasets demonstrate the clear edge of ScribbleDom over state-of-the-art methods-between 1.82% to 169.38% improvements in adjusted Rand index for 9 of the 12 human dorsolateral prefrontal cortex samples, and 15.54% improvement in the melanoma cancer dataset. Notably, when the expert input is absent, ScribbleDom can still operate, in a fully unsupervised manner like the state-of-the-art methods, and produces results that remain competitive. AVAILABILITY AND IMPLEMENTATION: Source code is available at Github (https://github.com/1alnoman/ScribbleDom) and Zenodo (https://zenodo.org/badge/latestdoi/681572669).

6.
BMC Health Serv Res ; 22(1): 1239, 2022 Oct 07.
Article in English | MEDLINE | ID: mdl-36207710

ABSTRACT

BACKGROUND: Hospital-acquired infections (HAIs) and antimicrobial resistance (AMR) are major global health challenges. Drug-resistant infectious diseases continue to rise in developing countries, driven by shortfalls in infection control measures, antibiotic misuse, and scarcity of reliable diagnostics. These escalating global challenges have highlighted the importance of strengthening fundamental infection prevention and control (IPC) measures and implementing effective antimicrobial stewardship programs (ASP). This study aims to present a framework for enhancing IPC measures and ASP efforts to reduce the HAI and AMR burden in Bangladesh. METHODS: This implementation approach will employ a mixed-methods strategy, combining both quantitative and qualitative data from 12 tertiary hospitals in Bangladesh. A baseline assessment will be conducted using the Infection Prevention and Control Assessment Framework (IPCAF) developed by the WHO. We will record IPC practices through direct observations of hand hygiene, personal protective equipment (PPE) utilization, and hospital ward IPC infrastructure. Additionally, data on healthcare providers' knowledge, attitudes, and practices regarding IPC and antibiotic prescribing will be collected using both structured questionnaires and qualitative interviews. We will also assist the hospital leadership with establishing and/or strengthening IPC and ASP committees. Based on baseline assessments of each healthcare facility, tailored interventions and quality improvement projects will be designed and implemented. An end-line assessment will also be conducted after 12 months of intervention using the same assessment tools. The findings will be compared with the baseline to determine changes in IPC and antibiotic stewardship practices. DISCUSSION: Comprehensive assessments of healthcare facilities in low-resource settings are crucial for strengthening IPC measures and ASP activities,. This approach to assessing existing IPC and ASP activities will provide policy-relevant data for addressing current shortfalls. Moreover, this framework proposes identifying institutionally-tailored solutions, which will ensure that response activities are appropriately contextualized, aligned with stakeholder priorities, and offer sustainable solutions. CONCLUSION: Findings from this study can guide the design and implementation of feasible and sustainable interventions in resource-constrained healthcare settings to address gaps in existing IPC and ASP activities. Therefore, this protocol will be applicable across a broad range of settings to improve IPC and ASP and reduce the burden of hospital-acquired infections and AMR.


Subject(s)
Antimicrobial Stewardship , Cross Infection , Anti-Bacterial Agents/therapeutic use , Bangladesh , Cross Infection/drug therapy , Cross Infection/prevention & control , Humans , Infection Control/methods
7.
BMC Microbiol ; 20(1): 270, 2020 08 28.
Article in English | MEDLINE | ID: mdl-32859152

ABSTRACT

BACKGROUND: The experimental materials were a 60-year-old tea tree (Camellia sinensis cv. Shu Cha Zao; SCZ) (the mother plant) and 1-year-old and 20-year-old plants of SCZ that originated as mother plant cuttings. The aim of this study was to use high-throughput sequencing to study the spatial and dynamic distribution of endophytic fungi in different leaf niches (upper leaves, middle leaves, lower leaves) and rhizosphere soil on tea plants of different ages in the same garden. RESULTS: Ascomycota (83.77%), Basidiomycota (11.71%), and Zygomycota (3.45%) were the dominant fungal phyla in all samples. Cladosporium (12.73%), Zymoseptoria (9.18%), and Strelitziana (13.11%) were the dominant genera in the leaf. Alpha diversity analysis revealed that endophytic communities in leaves differed from those in rhizosphere soil and different leaf niches had similar fungal diversity. Shannon's indices and NMDS analysis indicated significant differences in fungal diversity and composition among the SCZ trees of different ages (p ≤ 0.01). The abundance of Cladosporium and Zymoseptoria decreased with increasing SCZ age, whereas the abundance of Strelitziana increased. CONCLUSIONS: The results illustrate variation in endophytic fungi among different niches on tea plants of different ages. The distribution of endophytic fungi in leaves of C. sinensis shows spatiotemporal variation.


Subject(s)
Camellia sinensis/microbiology , Endophytes/physiology , Fungi , Biodiversity , Camellia sinensis/growth & development , Endophytes/genetics , Fungi/genetics , High-Throughput Nucleotide Sequencing , Plant Leaves/microbiology , Rhizosphere , Soil Microbiology , Spatio-Temporal Analysis
8.
Am J Dent ; 29(5): 251-254, 2016 Oct.
Article in English | MEDLINE | ID: mdl-29178736

ABSTRACT

PURPOSE: To compare the efficacy of using ozone versus hydrogen peroxide (H2O2) for tooth bleaching. METHODS: 90 extracted teeth were allocated into two groups. Teeth in Group 1 (n= 45) were exposed to ozone for 60 seconds; ozone was produced by healOzone x4 machine (healOzone x4), and was applied to teeth through special disposable silicone cups. The silicone cups allowed total seal and avoided gas escape as the machine is devised to work only if the cup guarantees perfect seal and thus secure the safety of the machine for human use. Teeth in Group 2 (n= 45) were treated with 38% H2O2 for 20 minutes. The shade of teeth was recorded for both groups at base line, after application of ozone in Group 1, and after application of H2O2 in Group 2. The reading for L* a* b* values and Vita Classic shades were recorded using the Colorimeter Konica-Minolta CR-400. The statistically significant differences were set at P≤ 0.05. RESULTS: The teeth in both groups acquired lighter shades after bleaching (P< 0.001). In addition, baseline L* shade values were increased and b* shade values were decreased (means lighter shades) after bleaching in both groups (P< 0.01). However, baseline a* shade values were not significantly changed after bleaching with ozone in Group 1 (P= 0.682). In contrast, a* shade values were significantly decreased after bleaching with H2O2 in Group 2 (P= 0.005). Furthermore, final shades achieved after bleaching were not significantly different between groups (P> 0.05). In conclusion, application of ozone for 60 seconds or application of 38% of H2O2 for 20 minutes resulted in teeth with lighter shades. Bleaching by application of ozone for 60 seconds would result in similar outcomes to bleaching with 38% H2O2. CLINICAL SIGNIFICANCE: This is the first study to compare bleaching effects of ozone and hydrogen peroxide on natural human teeth. It might be suitable to consider ozone for dental bleaching since comparing to H2O2 it could potentially reduce the time, side effects and cost of treatment. Also, application of ozone is better controlled and more convenient and measurable as it is delivered by a machine that can manage the concentration, volume, delivery site and timing of delivered ozone.


Subject(s)
Hydrogen Peroxide/pharmacology , Ozone/pharmacology , Tooth Bleaching Agents/pharmacology , Tooth Bleaching/methods , Tooth Discoloration/drug therapy , Colorimetry , Humans , In Vitro Techniques
9.
Mol Biol Evol ; 31(1): 184-200, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24097306

ABSTRACT

There is growing interest in models of regulatory sequence evolution. However, existing models specifically designed for regulatory sequences consider the independent evolution of individual transcription factor (TF)-binding sites, ignoring that the function and evolution of a binding site depends on its context, typically the cis-regulatory module (CRM) in which the site is located. Moreover, existing models do not account for the gene-specific roles of TF-binding sites, primarily because their roles often are not well understood. We introduce two models of regulatory sequence evolution that address some of the shortcomings of existing models and implement simulation frameworks based on them. One model simulates the evolution of an individual binding site in the context of a CRM, while the other evolves an entire CRM. Both models use a state-of-the art sequence-to-expression model to predict the effects of mutations on the regulatory output of the CRM and determine the strength of selection. We use the new framework to simulate the evolution of TF-binding sites in 37 well-studied CRMs belonging to the anterior-posterior patterning system in Drosophila embryos. We show that these simulations provide accurate fits to evolutionary data from 12 Drosophila genomes, which includes statistics of binding site conservation on relatively short evolutionary scales and site loss across larger divergence times. The new framework allows us, for the first time, to test hypotheses regarding the underlying cis-regulatory code by directly comparing the evolutionary implications of the hypothesis with the observed evolutionary dynamics of binding sites. Using this capability, we find that explicitly modeling self-cooperative DNA binding by the TF Caudal (CAD) provides significantly better fits than an otherwise identical evolutionary simulation that lacks this mechanistic aspect. This hypothesis is further supported by a statistical analysis of the distribution of intersite spacing between adjacent CAD sites. Experimental tests confirm direct homodimeric interaction between CAD molecules as well as self-cooperative DNA binding by CAD. We note that computational modeling of the D. melanogaster CRMs alone did not yield significant evidence to support CAD self-cooperativity. We thus demonstrate how specific mechanistic details encoded in CRMs can be revealed by modeling their evolution and fitting such models to multispecies data.


Subject(s)
Computer Simulation , Enhancer Elements, Genetic , Evolution, Molecular , Gene Expression Regulation , Animals , Binding Sites/genetics , Drosophila Proteins/genetics , Drosophila Proteins/metabolism , Drosophila melanogaster/genetics , Drosophila melanogaster/metabolism , Genome , Models, Genetic , Protein Binding , Sequence Analysis, DNA
10.
PLoS Comput Biol ; 10(3): e1003467, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24604095

ABSTRACT

Modeling a gene's expression from its intergenic locus and trans-regulatory context is a fundamental goal in computational biology. Owing to the distributed nature of cis-regulatory information and the poorly understood mechanisms that integrate such information, gene locus modeling is a more challenging task than modeling individual enhancers. Here we report the first quantitative model of a gene's expression pattern as a function of its locus. We model the expression readout of a locus in two tiers: 1) combinatorial regulation by transcription factors bound to each enhancer is predicted by a thermodynamics-based model and 2) independent contributions from multiple enhancers are linearly combined to fit the gene expression pattern. The model does not require any prior knowledge about enhancers contributing toward a gene's expression. We demonstrate that the model captures the complex multi-domain expression patterns of anterior-posterior patterning genes in the early Drosophila embryo. Altogether, we model the expression patterns of 27 genes; these include several gap genes, pair-rule genes, and anterior, posterior, trunk, and terminal genes. We find that the model-selected enhancers for each gene overlap strongly with its experimentally characterized enhancers. Our findings also suggest the presence of sequence-segments in the locus that would contribute ectopic expression patterns and hence were "shut down" by the model. We applied our model to identify the transcription factors responsible for forming the stripe boundaries of the studied genes. The resulting network of regulatory interactions exhibits a high level of agreement with known regulatory influences on the target genes. Finally, we analyzed whether and why our assumption of enhancer independence was necessary for the genes we studied. We found a deterioration of expression when binding sites in one enhancer were allowed to influence the readout of another enhancer. Thus, interference between enhancer activities was a possible factor necessitating enhancer independence in our model.


Subject(s)
DNA, Intergenic , Gene Expression Regulation , Models, Genetic , Algorithms , Animals , Computational Biology , Computer Simulation , Drosophila melanogaster , Enhancer Elements, Genetic , Gene Expression Profiling , Markov Chains , Models, Statistical , Monte Carlo Method , Regulatory Sequences, Nucleic Acid , Thermodynamics , Transcription Factors/metabolism
11.
Methods ; 62(1): 79-90, 2013 Jul 15.
Article in English | MEDLINE | ID: mdl-23624421

ABSTRACT

With the advent of high throughput sequencing and high resolution transcriptomic technologies, there exists today an unprecedented opportunity to understand gene regulation at a quantitative level. State of the art models of the relationship between regulatory sequence and gene expression have shown great promise, but also suffer from some major shortcomings. In this paper, we identify and address methodological challenges pertaining to quantitative modeling of gene expression from sequence, and test our models on the anterior-posterior patterning system in the Drosophila embryo. We first develop a framework to process cellular resolution three-dimensional gene expression data from the Drosophila embryo and create data sets on which quantitative models can be trained. Next we propose a new score, called 'weighted pattern generating potential' (w-PGP), to evaluate model predictions, and show its advantages over the two most common scoring schemes in use today. The model building exercise uses w-PGP as the evaluation score and adopts a systematic strategy to increase a model's complexity while guarding against over-fitting. Our model identifies three transcription factors--ZELDA, SLOPPY-PAIRED, and NUBBIN--that have not been previously incorporated in quantitative models of this system, as having significant regulatory influence. Finally, we show how fitting quantitative models on data sets comprising a handful of enhancers, as reported in earlier work, may lead to unreliable models.


Subject(s)
Drosophila Proteins/genetics , Drosophila melanogaster/genetics , Embryo, Nonmammalian/metabolism , Gene Expression Regulation, Developmental , Homeodomain Proteins/genetics , Models, Genetic , POU Domain Factors/genetics , Transcription Factors/genetics , Animals , Body Patterning/genetics , Cell Nucleus/genetics , Cell Nucleus/metabolism , Cell Nucleus/ultrastructure , Drosophila Proteins/metabolism , Drosophila melanogaster/embryology , Drosophila melanogaster/metabolism , Embryo, Nonmammalian/cytology , Embryo, Nonmammalian/ultrastructure , Gene Expression Profiling , Homeodomain Proteins/metabolism , Image Processing, Computer-Assisted/statistics & numerical data , Nuclear Proteins , POU Domain Factors/metabolism , Thermodynamics , Transcription Factors/metabolism , Transcription, Genetic
12.
Methods ; 62(1): 99-108, 2013 Jul 15.
Article in English | MEDLINE | ID: mdl-23726942

ABSTRACT

Deciphering the mechanisms involved in gene regulation holds the key to understanding the control of central biological processes, including human disease, population variation, and the evolution of morphological innovations. New experimental techniques including whole genome sequencing and transcriptome analysis have enabled comprehensive modeling approaches to study gene regulation. In many cases, it is useful to be able to assign biological significance to the inferred model parameters, but such interpretation should take into account features that affect these parameters, including model construction and sensitivity, the type of fitness calculation, and the effectiveness of parameter estimation. This last point is often neglected, as estimation methods are often selected for historical reasons or for computational ease. Here, we compare the performance of two parameter estimation techniques broadly representative of local and global approaches, namely, a quasi-Newton/Nelder-Mead simplex (QN/NMS) method and a covariance matrix adaptation-evolutionary strategy (CMA-ES) method. The estimation methods were applied to a set of thermodynamic models of gene transcription applied to regulatory elements active in the Drosophila embryo. Measuring overall fit, the global CMA-ES method performed significantly better than the local QN/NMS method on high quality data sets, but this difference was negligible on lower quality data sets with increased noise or on data sets simplified by stringent thresholding. Our results suggest that the choice of parameter estimation technique for evaluation of gene expression models depends both on quality of data, the nature of the models [again, remains to be established] and the aims of the modeling effort.


Subject(s)
Algorithms , Drosophila melanogaster/genetics , Embryo, Nonmammalian/metabolism , Gene Expression Regulation, Developmental , Models, Genetic , Systems Biology/methods , Animals , Drosophila melanogaster/embryology , Drosophila melanogaster/metabolism , Embryo, Nonmammalian/cytology , Gene Expression Profiling , Humans , Thermodynamics , Transcription, Genetic
13.
Am J Infect Control ; 2024 May 23.
Article in English | MEDLINE | ID: mdl-38795902

ABSTRACT

BACKGROUND: Prevalent use of antibiotics in hospitals results in antimicrobial resistance (AMR), rising mortality, and substantial financial burden. This study assessed the current pattern of antibiotic use among inpatients in tertiary hospitals in Bangladesh. METHODS: Between August and November 2022, we conducted a point prevalence survey in 4 tertiary hospitals in Dhaka, Bangladesh. The World Health Organization-directed point prevalence survey methodology and tools were followed for the data collection. Descriptive and multivariate statistics were performed using Stata version 15. RESULTS: Of 1,063 hospitalized patients, antibiotics were prescribed to 73.5% (781/1063, 95% confidence interval: 70.8-76.1) of patients. A total of 1,164 antibiotics were prescribed, and 49.1% of patients consumed multiple antibiotics. Only 31.4% of patients were prescribed antibiotics based on microbiology results. The reasons for antibiotic prescribing were mentioned only in 19.3% of patients. Infants (adjusted odds ratio: 8.52, P-value: <.001) and neonates (adjusted odds ratio: 4.32, P-value: <.001) were more likely to consume antibiotics compared to adults. Cephalosporins accounted for the majority (54.0%) of antibiotics used in hospitals. None of the hospitals had any antibiotic use guidelines. CONCLUSIONS: Consumption of Watch group antibiotics empirically among all age groups demonstrates irrational antibiotic usage in Bangladeshi hospitals. Implementation of a tailored stewardship program, antibiotic use guidelines, and prescriber-patient awareness could improve the rational use of antibiotics.

14.
Genome Biol ; 25(1): 57, 2024 02 26.
Article in English | MEDLINE | ID: mdl-38408997

ABSTRACT

A critical challenge of single-cell spatial transcriptomics (sc-ST) technologies is their panel size. Being based on fluorescence in situ hybridization, they are typically limited to panels of about a thousand genes. This constrains researchers to build panels from only the marker genes of different cell types and forgo other genes of interest, e.g., genes encoding ligand-receptor complexes or those in specific pathways. We propose scGIST, a constrained feature selection tool that designs sc-ST panels prioritizing user-specified genes without compromising cell type detection accuracy. We demonstrate scGIST's efficacy in diverse use cases, highlighting it as a valuable addition to sc-ST's algorithmic toolbox.


Subject(s)
Gene Expression Profiling , Transcriptome , In Situ Hybridization, Fluorescence
15.
Life Sci Alliance ; 7(2)2024 02.
Article in English | MEDLINE | ID: mdl-38012001

ABSTRACT

Modulation of the heart's immune microenvironment is crucial for recovery after ischemic events such as myocardial infarction (MI). Endothelial cells (ECs) can have immune regulatory functions; however, interactions between ECs and the immune environment in the heart after MI remain poorly understood. We identified an EC-specific IFN responsive and immune regulatory gene signature in adult and pediatric heart failure (HF) tissues. Single-cell transcriptomic analysis of murine hearts subjected to MI uncovered an EC population (IFN-ECs) with immunologic gene signatures similar to those in human HF. IFN-ECs were enriched in regenerative-stage mouse hearts and expressed genes encoding immune responsive transcription factors (Irf7, Batf2, and Stat1). Single-cell chromatin accessibility studies revealed an enrichment of these TF motifs at IFN-EC signature genes. Expression of immune regulatory ligand genes by IFN-ECs suggests bidirectional signaling between IFN-ECs and macrophages in regenerative-stage hearts. Our data suggest that ECs may adopt immune regulatory signatures after cardiac injury to accompany the reparative response. The presence of these signatures in human HF and murine MI models suggests a potential role for EC-mediated immune regulation in responding to stress induced by acute injury in MI and chronic adverse remodeling in HF.


Subject(s)
Heart Failure , Myocardial Infarction , Mice , Humans , Animals , Child , Endothelial Cells/metabolism , Myocardial Infarction/genetics , Myocardial Infarction/metabolism , Heart , Signal Transduction/genetics
16.
Nat Cardiovasc Res ; 3(3): 283-300, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38510108

ABSTRACT

After myocardial infarction (MI), mammalian hearts do not regenerate, and the microenvironment is disrupted. Hippo signaling loss of function with activation of transcriptional co-factor YAP induces heart renewal and rebuilds the post-MI microenvironment. In this study, we investigated adult renewal-competent mouse hearts expressing an active version of YAP, called YAP5SA, in cardiomyocytes (CMs). Spatial transcriptomics and single-cell RNA sequencing revealed a conserved, renewal-competent CM cell state called adult (a)CM2 with high YAP activity. aCM2 co-localized with cardiac fibroblasts (CFs) expressing complement pathway component C3 and macrophages (MPs) expressing C3ar1 receptor to form a cellular triad in YAP5SA hearts and renewal-competent neonatal hearts. Although aCM2 was detected in adult mouse and human hearts, the cellular triad failed to co-localize in these non-renewing hearts. C3 and C3ar1 loss-of-function experiments indicated that C3a signaling between MPs and CFs was required to assemble the pro-renewal aCM2, C3+ CF and C3ar1+ MP cellular triad.

17.
Nat Commun ; 15(1): 538, 2024 Jan 15.
Article in English | MEDLINE | ID: mdl-38225226

ABSTRACT

Hematopoietic stem cells (HSCs) are capable of regenerating the blood system, but the instructive cues that direct HSCs to regenerate particular lineages lost to the injury remain elusive. Here, we show that iron is increasingly taken up by HSCs during anemia and induces erythroid gene expression and regeneration in a Tet2-dependent manner. Lineage tracing of HSCs reveals that HSCs respond to hemolytic anemia by increasing erythroid output. The number of HSCs in the spleen, but not bone marrow, increases upon anemia and these HSCs exhibit enhanced proliferation, erythroid differentiation, iron uptake, and TET2 protein expression. Increased iron in HSCs promotes DNA demethylation and expression of erythroid genes. Suppressing iron uptake or TET2 expression impairs erythroid genes expression and erythroid differentiation of HSCs; iron supplementation, however, augments these processes. These results establish that the physiological level of iron taken up by HSCs has an instructive role in promoting erythroid-biased differentiation of HSCs.


Subject(s)
Anemia , Dioxygenases , Humans , Spleen , Hematopoietic Stem Cells/metabolism , Cell Differentiation , Iron/metabolism , Anemia/metabolism , Erythroid Cells , DNA-Binding Proteins/metabolism , Dioxygenases/metabolism
18.
BMC Pregnancy Childbirth ; 13: 11, 2013 Jan 16.
Article in English | MEDLINE | ID: mdl-23324222

ABSTRACT

BACKGROUND: The maternal near-miss concept has been developed as an instrument for assisting health systems to evaluate and improve their quality of care. Our study aimed at studying the characteristics and quality of care provided to women with severe complications in Baghdad through the use of the World Health Organization (WHO) near-miss approach for maternal health. METHODS: This is a facility-based, cross-sectional study conducted in 6 public hospitals in Baghdad between March 1, 2010 and the June 30, 2010. WHO near-miss approach was utilized to analyze the data in terms of indicators of maternal near miss and access to and quality of maternal care. RESULTS: The maternal near-miss rate was low at 5.06 per 1,000 live births, while the overall maternal near miss: mortality ratio was 9:1. One third of the near-miss cases were referred from other facilities and the mortality index was the same for referred women and for in-hospital women (11%). The intensive care unit (ICU) admission rate was 37% for women with severe maternal outcomes (SMO), while the overall admission rate was 0.28%. Anemia (55%) and previous cesarean section (45%) were the most common associated conditions with severe maternal morbidity. The use of magnesium sulfate for treatment of eclampsia, oxytocin for prevention and treatment of postpartum hemorrhage, prophylactic antibiotics during caesarean section, and corticosteroids for inducing fetal lung maturation in preterm birth is suboptimum. CONCLUSIONS: The WHO near-miss approach allowed systematic identification of the roadblocks to improve quality of care and then monitoring the progress. Critical evidence-based practices, relevant to the management of women experiencing life-threatening conditions, are underused. In addition, possible limitations in the referral system result in a very high proportion of women presenting at the hospital already in a severe health condition (i.e. with organ dysfunction). A shortage of ICU beds leading to women taken care of without admission to ICU may also contribute to a high proportion of maternal deaths and organ dysfunction.


Subject(s)
Maternal Health Services/organization & administration , Obstetric Labor Complications/epidemiology , Outcome and Process Assessment, Health Care/methods , Pregnancy Complications/epidemiology , Adult , Cross-Sectional Studies , Female , Hospitals, Maternity , Hospitals, Public , Humans , Infant, Newborn , Intensive Care Units/statistics & numerical data , Iraq/epidemiology , Maternal Health Services/statistics & numerical data , Morbidity , Obstetric Labor Complications/etiology , Obstetric Labor Complications/therapy , Outcome and Process Assessment, Health Care/statistics & numerical data , Pregnancy , Pregnancy Complications/etiology , Pregnancy Complications/therapy , Prevalence , World Health Organization
19.
Mol Biol Cell ; 34(9)2023 08 01.
Article in English | MEDLINE | ID: mdl-37486893

ABSTRACT

Transcription factors (TFs) are one of the most studied classes of DNA-binding proteins that have a direct functional impact on gene transcription and thus, on human physiology and disease. The mechanisms that TFs use for recognizing target DNA binding sites have been studied for nearly five decades, yet they remain poorly understood. It is classically assumed that a TF recognizes a specific sequence pattern, or motif, as its binding sites. However, recent studies are consistently finding examples of noncanonical binding, that is, TFs binding at sites that do not resemble their sequence motifs. Here we review the current literature on four major types of noncanonical TF binding, namely binding based on DNA shape readout, at Guanine-quadruplex structures, at repeat sequences, and bispecific binding. These examples point to a critical need for studies to unify our current observations, many of which are at odds with the "one TF, one motif" view, into a more comprehensive definition of the DNA-binding specificity of TFs.


Subject(s)
DNA-Binding Proteins , Transcription Factors , Humans , Binding Sites
20.
iScience ; 26(2): 105945, 2023 Feb 17.
Article in English | MEDLINE | ID: mdl-36866046

ABSTRACT

The bendability of genomic DNA impacts chromatin packaging and protein-DNA binding. However, we do not have a comprehensive understanding of the motifs influencing DNA bendability. Recent high-throughput technologies such as Loop-Seq offer an opportunity to address this gap but the lack of accurate and interpretable machine learning models still remains. Here we introduce DeepBend, a convolutional neural network model with convolutions designed to directly capture the motifs underlying DNA bendability and their periodic occurrences or relative arrangements that modulate bendability. DeepBend consistently performs on par with alternative models while giving an extra edge through mechanistic interpretations. Besides confirming the known motifs of DNA bendability, DeepBend also revealed several novel motifs and showed how the spatial patterns of motif occurrences influence bendability. DeepBend's genome-wide prediction of bendability further showed how bendability is linked to chromatin conformation and revealed the motifs controlling the bendability of topologically associated domains and their boundaries.

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