The transcription factor NFIL3/E4BP4 regulates the developmental stage-specific acquisition of basophil function.

BACKGROUND: Basophils are rare but important effector cells in many allergic disorders. Contrary to their early progenitors, the terminal developmental processes of basophils in which they gain their unique functional properties are unknown. OBJECTIVE: We sought to identify a novel late-stage basophil precursor and a transcription factor regulating the terminal maturation of basophils. METHODS: Using flow cytometry, transcriptome analysis, and functional assays, we investigated the identification and functionality of the basophil precursors as well as basophil development. We generated mice with basophil-specific deletion of nuclear factor IL-3 (NFIL3)/E4BP4 and analyzed the functional impairment of NFIL3/E4BP4-deficient basophils in vitro and in vivo using an oxazolone-induced murine model of allergic dermatitis. RESULTS: We report a new mitotic transitional basophil precursor population (referred to as transitional basophils) that expresses the FcεRIα chain at higher levels than mature basophils. Transitional basophils are less responsive to IgE-linked degranulation but produce more cytokines in response to IL-3, IL-33, or IgE cross-linking than mature basophils. In particular, we found that the expression of NFIL3/E4BP4 gradually rises as cells mature from the basophil progenitor stage. Basophil-specific deletion of NFIL3/E4BP4 reduces the expression of genes necessary for basophil function and impairs IgE receptor signaling, cytokine secretion, and degranulation in the context of murine atopic dermatitis. CONCLUSIONS: We discovered transitional basophils, a novel late-stage mitotic basophil precursor cell population that exists between basophil progenitors and postmitotic mature basophils. We demonstrated that NFIL3/E4BP4 augments the IgE-mediated functions of basophils, pointing to a potential therapeutic regulator for allergic diseases.

DeepLUCIA: predicting tissue-specific chromatin loops using Deep Learning-based Universal Chromatin Interaction Annotator.

MOTIVATION: The importance of chromatin loops in gene regulation is broadly accepted. There are mainly two approaches to predict chromatin loops: transcription factor (TF) binding-dependent approach and genomic variation-based approach. However, neither of these approaches provides an adequate understanding of gene regulation in human tissues. To address this issue, we developed a deep learning-based chromatin loop prediction model called Deep Learning-based Universal Chromatin Interaction Annotator (DeepLUCIA). RESULTS: Although DeepLUCIA does not use TF binding profile data which previous TF binding-dependent methods critically rely on, its prediction accuracies are comparable to those of the previous TF binding-dependent methods. More importantly, DeepLUCIA enables the tissue-specific chromatin loop predictions from tissue-specific epigenomes that cannot be handled by genomic variation-based approach. We demonstrated the utility of the DeepLUCIA by predicting several novel target genes of SNPs identified in genome-wide association studies targeting Brugada syndrome, COVID-19 severity and age-related macular degeneration. Availability and implementation DeepLUCIA is freely available at https://github.com/bcbl-kaist/DeepLUCIA. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

3DIV: A 3D-genome Interaction Viewer and database.

Three-dimensional (3D) chromatin structure is an emerging paradigm for understanding gene regulation mechanisms. Hi-C (high-throughput chromatin conformation capture), a method to detect long-range chromatin interactions, allows extensive genome-wide investigation of 3D chromatin structure. However, broad application of Hi-C data have been hindered by the level of complexity in processing Hi-C data and the large size of raw sequencing data. In order to overcome these limitations, we constructed a database named 3DIV (a 3D-genome Interaction Viewer and database) that provides a list of long-range chromatin interaction partners for the queried locus with genomic and epigenomic annotations. 3DIV is the first of its kind to collect all publicly available human Hi-C data to provide 66 billion uniformly processed raw Hi-C read pairs obtained from 80 different human cell/tissue types. In contrast to other databases, 3DIV uniquely provides normalized chromatin interaction frequencies against genomic distance dependent background signals and a dynamic browsing visualization tool for the listed interactions, which could greatly advance the interpretation of chromatin interactions. '3DIV' is available at http://kobic.kr/3div.

A new class of constitutively active super-enhancers is associated with fast recovery of 3D chromatin loops.

BACKGROUND: Super-enhancers or stretch enhancers are clusters of active enhancers that often coordinate cell-type specific gene regulation during development and differentiation. In addition, the enrichment of disease-associated single nucleotide polymorphism in super-enhancers indicates their critical function in disease-specific gene regulation. However, little is known about the function of super-enhancers beyond gene regulation. RESULTS: In this study, through a comprehensive analysis of super-enhancers in 30 human cell/tissue types, we identified a new class of super-enhancers which are constitutively active across most cell/tissue types. These 'common' super-enhancers are associated with universally highly expressed genes in contrast to the canonical definition of super-enhancers that assert cell-type specific gene regulation. In addition, the genome sequence of these super-enhancers is highly conserved by evolution and among humans, advocating their universal function in genome regulation. Integrative analysis of 3D chromatin loops demonstrates that, in comparison to the cell-type specific super-enhancers, the cell-type common super-enhancers present a striking association with rapidly recovering loops. CONCLUSIONS: In this study, we propose that a new class of super-enhancers may play an important role in the early establishment of 3D chromatin structure.

Characterization of altered molecular mechanisms in Parkinson's disease through cell type-resolved multiomics analyses.

Parkinson's disease (PD) is a progressive neurodegenerative disorder. However, cell type-dependent transcriptional regulatory programs responsible for PD pathogenesis remain elusive. Here, we establish transcriptomic and epigenomic landscapes of the substantia nigra by profiling 113,207 nuclei obtained from healthy controls and patients with PD. Our multiomics data integration provides cell type annotation of 128,724 cis-regulatory elements (cREs) and uncovers cell type-specific dysregulations in cREs with a strong transcriptional influence on genes implicated in PD. The establishment of high-resolution three-dimensional chromatin contact maps identifies 656 target genes of dysregulated cREs and genetic risk loci, uncovering both potential and known PD risk genes. Notably, these candidate genes exhibit modular gene expression patterns with unique molecular signatures in distinct cell types, highlighting altered molecular mechanisms in dopaminergic neurons and glial cells including oligodendrocytes and microglia. Together, our single-cell transcriptome and epigenome reveal cell type-specific disruption in transcriptional regulations related to PD.

A compendium of promoter-centered long-range chromatin interactions in the human genome.

A large number of putative cis-regulatory sequences have been annotated in the human genome, but the genes they control remain poorly defined. To bridge this gap, we generate maps of long-range chromatin interactions centered on 18,943 well-annotated promoters for protein-coding genes in 27 human cell/tissue types. We use this information to infer the target genes of 70,329 candidate regulatory elements and suggest potential regulatory function for 27,325 noncoding sequence variants associated with 2,117 physiological traits and diseases. Integrative analysis of these promoter-centered interactome maps reveals widespread enhancer-like promoters involved in gene regulation and common molecular pathways underlying distinct groups of human traits and diseases.

Inflammation induces two types of inflammatory dendritic cells in inflamed lymph nodes.

The spatiotemporal regulation of immune cells in lymph nodes (LNs) is crucial for mounting protective T-cell responses, which are orchestrated by dendritic cells (DCs). However, it is unclear how the DC subsets are altered by the inflammatory milieu of LNs. Here, we show that the inflamed LNs of Listeria-infected mice are characterized by the clustering of neutrophils and monocytes and IFN-γ production. Significantly, the early inflammatory responses are coupled with the differentiation of not one, but two types of CD64+CD11c+MHCII+ inflammatory DCs. Through the assessment of chemokine receptor dependency, gene expression profiles, growth factor requirements and DC-specific lineage mapping, we herein unveil a novel inflammatory DC population (we termed 'CD64+ cDCs') that arises from conventional DCs (cDCs), distinguishable from CD64+ monocyte-derived DCs (moDCs) in inflamed LNs. We determined that Listeria-induced type I IFN is a critical inflammatory cue for the development of CD64+ cDCs but not CD64+ moDCs. Importantly, CD64+ cDCs displayed a higher potential to activate T cells than CD64+ moDCs, whereas the latter showed more robust expression of inflammatory genes. Although CD64+ and CD64- cDCs were able to cross-present soluble antigens at a high dose to CD8+ T cells, CD64+ cDCs concentrated and cross-presented a minute amount of soluble antigens delivered via CD64 (FcγRI) as immune complexes. These findings reveal the role of early inflammatory responses in driving the differentiation of two inflammatory DC subsets empowered with distinct competencies.

Publisher Correction: Inflammation induces two types of inflammatory dendritic cells in inflamed lymph nodes.

The original version of this article unfortunately contained an error in the author name Dongchan Yang, which was incorrectly given as Dongchan Yang Sung.

The human noncoding genome defined by genetic diversity.

Understanding the significance of genetic variants in the noncoding genome is emerging as the next challenge in human genomics. We used the power of 11,257 whole-genome sequences and 16,384 heptamers (7-nt motifs) to build a map of sequence constraint for the human species. This build differed substantially from traditional maps of interspecies conservation and identified regulatory elements among the most constrained regions of the genome. Using new Hi-C experimental data, we describe a strong pattern of coordination over 2 Mb where the most constrained regulatory elements associate with the most essential genes. Constrained regions of the noncoding genome are up to 52-fold enriched for known pathogenic variants as compared to unconstrained regions (21-fold when compared to the genome average). This map of sequence constraint across thousands of individuals is an asset to help interpret noncoding elements in the human genome, prioritize variants and reconsider gene units at a larger scale.

A late-lineage murine neutrophil precursor population exhibits dynamic changes during demand-adapted granulopoiesis.

Homeostasis of neutrophils-the blood cells that respond first to infection and tissue injury-is critical for the regulation of immune responses and regulated through granulopoiesis, a multi-stage process by which neutrophils differentiate from hematopoietic stem cells. Granulopoiesis is a highly dynamic process and altered in certain clinical conditions, such as pathologic and iatrogenic neutropenia, described as demand-adapted granulopoiesis. The regulation of granulopoiesis under stress is not completely understood because studies of granulopoiesis dynamics have been hampered by technical limitations in defining neutrophil precursors. Here, we define a population of neutrophil precursor cells in the bone marrow with unprecedented purity, characterized by the lineage-CD11b+Ly6GloLy6BintCD115-, which we call NeuPs (Neutrophil Precursors). We demonstrated that NeuPs differentiate into mature and functional neutrophils both in vitro and in vivo. By analyzing the gene expression profiles of NeuPs, we also identified NeuP stage-specific genes and characterized patterns of gene regulation throughout granulopoiesis. Importantly, we found that NeuPs have the potential to proliferate, but the proliferation decreased in multiple different hematopoietic stress settings, indicating that proliferating NeuPs are poised at a critical step to regulate granulopoiesis. Our findings will facilitate understanding how the hematopoietic system maintains homeostasis and copes with the demands of granulopoiesis.

Increased Bolus Volume Effect on Delayed Pharyngeal Swallowing Response in Post-stroke Oropharyngeal Dysphagia: A Pilot Study.

OBJECTIVE: To confirm a relationship between the pharyngeal response and bolus volume, and examine whether increasing the fluid bolus volume can improve penetration and aspiration for stroke dysphagic patients. METHODS: Ten stroke patients with a delayed pharyngeal response problem confirmed by a videofluoroscopic swallowing study (VFSS) were enrolled. Each subject completed two swallows each of 2 mL, 5 mL, and 10 mL of barium liquid thinned with water. The pharyngeal delay time (PDT) and penetration-aspiration scale (PAS) were measured and the changes among the different volumes were analyzed. RESULTS: PDTs were shortened significantly when 5 mL and 10 mL of thin barium were swallowed compared to 2 mL. However, there was no significant difference in PAS as the bolus volume increased. CONCLUSION: The increased fluid bolus volume reduced the pharyngeal delay time, but did not affect the penetration and aspiration status.