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Wu, L.

Publications and source records attributed to Wu, L..

At least 325 records · Page 18Linked to original sources

An ATAC-seq atlas of chromatin accessibility in mouse tissues

The Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq) is a fundamental epigenomics approach and has been widely used in profiling the chromatin accessibility dynamics in multiple species. A comprehensive reference of ATAC-seq datasets for mammalian tissues is important for the understanding of regulatory specificity and developmental abnormality caused by genetic or environmental alterations. Here, we report an adult mouse ATAC-seq atlas by producing a total of 66 ATAC-seq profiles from 20 primary tissues of both male and female mice. The ATAC-seq read enrichment, fragment size distribution, and reproducibility between replicates demonstrated the high quality of the full dataset. We identified a total of 296,574 accessible elements, of which 26,916 showed tissue-specific accessibility. Further, we identified key transcription factors specific to distinct tissues and found that the enrichment of each motif reflects the developmental similarities across tissues. In summary, our study provides an important resource on the mouse epigenome and will be of great importance to various scientific disciplines such as development, cell reprogramming, and genetic disease.

genomics↗

Effects of topical PaiTeLing in nude mice implanted with human condyloma acuminatum tissue infected with HPV 6, 31, and 81: comparison with imiquimod and interferon-α-2b

BACKGROUNDThe standard treatment for condyloma acuminatum is topical imiquimod. In the current study, we used a mouse model to compare the effects of an herbal medication PaiTeLing. METHODSLesion tissue was obtained from a woman with genital condyloma acuminatum. DNA genotyping revealed HPV6, 31, and 81. Tissue prism (0.5 cm3) was implanted to BALB/C nude mice, 22 days after the implantation, mice began to receive topical treatment with imiquimod, interferon--2b gel, or PaiTeLing over the site of implantation for 2 consecutive weeks. Mice receiving tissue implantation but no other intervention was included as a control. Skin tissue was collected for H&E staining and anti-CD207 immunohistochemistry. Blood was collected to determine a panel of cytokines. RESULTSH&E staining showed lower number of koilocytes and higher number of Langerhans cells in the treatment groups, particularly in mice receiving imiquimod or PaiTeLing. Blood levels of TNF, IL-2, INF-{gamma} and IL-12p70 were increased in the treatment groups, particularly in mice receiving imiquimod or PaiTeLing. CONCLUSIONImmune response in nude mice infected with HPV6, 31, and 81 is enhanced by treatment with imiquimod, interferon--2b and PaiTeLing. Effects of imiquimod and PaiTeLing seems to be stronger than interferon--2b.

immunology↗

High-throughput single-particle tracking reveals nested membrane nanodomain organization that dictates Ras diffusion and trafficking

Membrane nanodomains have been implicated in Ras signaling, but what these domains are and how they interact with Ras remain obscure. Using high throughput single particle tracking with photoactivated localization microscopy and detailed trajectory analysis, here we show that distinct membrane domains dictate KRas diffusion and trafficking in U2OS cells. KRas exhibits an immobile state in domains [~]70 nm in size, each embedded in a larger domain ([~]200 nm) that confers intermediate mobility, while the rest of the membrane supports fast diffusion. Moreover, KRas is continuously removed from the membrane via the immobile state and replenished to the fast state, likely coupled to internalization and recycling. Importantly, both the diffusion and trafficking properties of KRas remain invariant over a broad range of protein expression levels. Our results reveal how membrane organization dictates KRas diffusion and trafficking and offer insight into how Ras signaling may be regulated through spatial mechanisms.

biophysics↗

IL-10-producing B cells are enriched in murine pericardial adipose tissues and ameliorate the outcome of acute myocardial infarction

Acute myocardial infarction (MI) provokes an inflammatory response in the heart that removes damaged tissues to facilitate repair. However, exaggerated and/or persistent inflammation compromises healing, which may be counteracted by regulatory immune mechanisms. A key regulatory factor in an inflammatory response is the anti-inflammatory cytokine IL-10, which can be produced by a number of immune cells including subsets of B lymphocytes. Here, we investigated IL-10-producing B cells in pericardial adipose tissues (PATs) and their role in the healing process following acute MI in mice. We found abundant IL-10-producing B cells in PATs under homeostatic conditions, with the majority of them bearing cell surface CD5 (CD5+ B cells). These cells were detected early in life, maintained a steady presence during adulthood, and resided in fat-associated lymphoid clusters (FALCs). The cytokine IL-33 was preferentially expressed in PATs under homeostatic conditions and contributed to enrichment of IL-10-producing CD5+ B cells in PATs. CD5+ B cells expanded in PATs following MI, and accumulated in the infarcted heart during the resolution of MI-induced inflammation. B cell-specific deletion of IL-10 worsened cardiac function after MI, exacerbated myocardial injury, and delayed resolution of inflammation. These findings reveal a significant contribution of IL-10-producing B cells to the anti-inflammatory mechanism that terminates MI-induced inflammation, and identify these cells as novel therapeutic targets to improve the outcome of MI. Significance StatementMyocardial infarction (MI) remains a leading cause of mortality and morbidity worldwide. Although it is now recognized that a balanced and timely terminated pro-inflammatory response following acute MI is essential in promoting tissue repair, the underlying regulatory mechanisms are poorly defined. In this report, we show that IL-10-producing B cells in mice 1) are enriched in pericardial adipose tissues (PATs) and influenced by cytokine IL-33 under homeostatic conditions; 2) expand in PATs following MI and accumulate in the infarcted heart during the resolution of MI-induced inflammation; and 3) facilitate resolution of inflammation and reduce myocardial injury to preserve cardiac function after MI. These findings identify IL-10-producing B cells as novel therapeutic targets to improve the outcome of MI.

immunology↗

Bile acid metabolites control Th17 and Treg cell differentiation

Bile acids are abundantly present in the mammalian gut, where they undergo bacteria-mediated transformation, generating a large pool of bioactive molecules. While they have been shown to affect host metabolism, cancer progression and innate immunity, it is unknown whether bile acids affect the function of adaptive immune cells such as T cells expressing IL-17a (Th17 cells) and regulatory T cells (Tregs) that mediate inflammatory and anti-inflammatory responses, respectively. By screening a small-molecule library primarily composed of bile acid metabolites, we identified two distinct derivatives of lithocholic acid (LCA), 3-oxoLCA and isoalloLCA, as specific regulators of Th17 and Treg cells. While 3-oxoLCA inhibited Th17 cell differentiation by directly binding to its key transcription factor ROR{gamma}t (retinoid-related orphan receptor {gamma} t), isoalloLCA enhanced differentiation of Tregs through mitochondrial-dependent metabolic changes, leading to an increased expression of Foxp3. IsoalloLCA-dependent Treg enhancement required an intronic Foxp3 enhancer, the conserved noncoding sequence 3 (CNS3), which acts as an epigenetic switch that confers a poised state to the Foxp3 promoter. Lastly, oral administration of 3-oxoLCA and isoalloLCA to mice led to reduced Th17 and increased Treg cell differentiation in the intestinal lamina propria. Altogether, our data suggest novel mechanisms by which bile acid metabolites control host immune responses by directly modulating the Th17 and Treg balance.

immunology↗

PARIS, an optogenetic method for functionally mapping gap junctions

Cell-cell communication via gap junctions regulates a wide range of physiological processes by enabling the direct intercellular electrical and chemical coupling. However, the in vivo distribution and function of gap junctions remain poorly understood, partly due to the lack of non-invasive tools with both cell-type specificity and high spatiotemporal resolution. Here we developed PARIS (pairing actuators and receivers to optically isolate gap junctions), a new fully genetically encoded tool for measuring the cell-specific gap junctional coupling (GJC). PARIS successfully enabled monitoring of GJC in several cultured cell lines under physiologically relevant conditions and in distinct genetically defined neurons in Drosophila brain, with ~10-sec temporal resolution and sub-cellular spatial resolution. These results demonstrate that PARIS is a robust, highly sensitive tool for mapping functional gap junctions and study their regulation in both health and disease.

neuroscience↗

Comparative analysis of sequencing technologies platforms for single-cell transcriptomics

All single-cell RNA-seq protocols and technologies require library preparation prior to sequencing on a platform such as Illumina. Here, we present the first report to utilize the BGISEQ-500 platform for scRNA-seq, and compare the sensitivity and accuracy to Illumina sequencing. We generate a scRNA-seq resource of 468 unique single-cells and 1,297 matched single cDNA samples, performing SMARTer and Smart-seq2 protocols on mESCs and K562 cells with RNA spike-ins. We sequence these libraries on both BGISEQ-500 and Illumina HiSeq platforms using single- and paired-end reads. The two platforms have comparable sensitivity and accuracy in terms of quantification of gene expression, and low technical variability. Our study provides a standardised scRNA-seq resource to benchmark new scRNA-seq library preparation protocols and sequencing platforms.

genomics↗

scRMD: Imputation for single cell RNA-seq data via robust matrix decomposition

MotivationSingle cell RNA-sequencing (scRNA-seq) technology enables whole transcriptome profiling at single cell resolution and holds great promises in many biological and medical applications. Nevertheless, scRNA-seq often fails to capture expressed genes, leading to the prominent dropout problem. These dropouts cause many problems in down-stream analysis, such as significant noise increase, power loss in differential expression analysis and obscuring of gene-to-gene or cell-to-cell relationship. Imputation of these dropout values thus becomes an essential step in scRNA-seq data analysis.\n\nResultsIn this paper, we model the dropout imputation problem as robust matrix decomposition. This model has minimal assumptions and allows us to develop a computational efficient imputation method scRMD. Extensive data analysis shows that scRMD can accurately recover the dropout values and help to improve downstream analysis such as differential expression analysis and clustering analysis.\n\nContactruibinxi@math.pku.edu.cn

bioinformatics↗

Genetic Association of The CYP7A1 Gene with Duck Lipid Traits

Cholesterol 7-hydroxylase (Cyp7a1) participates in lipid metabolism of liver, and its pathway involves catabolism of cholesterol to bile acids and excretion from the body. However, little is known about the effect of the polymorphisms of CYP7A1 gene on duck lipid traits. In the present study, seven novel synonymous mutations loci in exon 2 and exon 3 of CYP7A1 gene in Cherry Valley ducks were identified using PCR production direct sequencing. One novel SNP g.1033130 C>T was predicted in exon 2. Six novel SNPs g.1034076 C>T, g.1034334 G>A, g.1034373 G>A, g.1034448 T>C, g.1034541 C>G, and g.1034550 G>A were discovered in exon 3. Six haplotypes were detected using SHEsis online analysis software, and five loci (g.1034334G>A, g.1034373G>A, g.1034448T>C, g.1034541C>G, and g.1034550G>A) were in complete linkage disequilibrium, and as a block named Locus C3. By single SNP association analysis, we found that the g.1033130 C>T locus was significantly associated with IMF, AFP, TG, and TC (P<0.01 or P<0.05) respectively, the g.1034076 C>T locus was significantly associated with AFP (P<0.05), and the locus C3 was significantly associated with TCH (P<0.05). Sixteen dipoltypes were detected by the combination of haplotypes, and demonstrated strong association with IMF, AFP, TG, and TCH (P<0.01). Therefore, our data suggested that the seven SNPs of CYP7A1 gene are potential markers for lipid homeostasis, and may be used for early breeding and selection of duck.

genetics↗

The Evolutionary Landscape of Pan-Cancer Drives Clinical Aggression

Although cancer mechanisms differ from occurrence and development, some of them have similar oncogenesis, which leads to similar clinical phenotypes. Most existing genotyping studies look at \"omics\" data, but intentionally or unintentionally avoided that cancer is a time-dependent evolutionary process, biologically represented by the time evolution of tumor clones. We used the Bayesian mutation landscape approach to reconstruct the evolutionary process of cancer by acquiring somatic mutation data consisting of 21 cancer types. Four representative evolution patterns of pan-cancer have been discovered: trees, chaos, biconvex, and Cambrian, and a strong correlation between these four evolutionary patterns and clinical aggressivity. We further explained the characteristics of the corresponding biological systems in the evolution of pan cancer by analyzing the function of differentially expressed protein-protein interaction networks. Our results explained the difference in clinical aggressivity between cancer evolution patterns from the evolution of tumor clones and exposed the functional mechanism behind.

cancer biology↗

Single-cell RNA-seq reveals dynamic transcriptome profiling in human early neural differentiation

BackgroundInvestigating cell fate decision and subpopulation specification in the context of the neural lineage is fundamental to understanding neurogenesis and neurodegenerative diseases. The differentiation process of neural-tube-like rosettes in vitro is representative of neural tube structures, which are composed of radially organized, columnar epithelial cells and give rise to functional neural cells. However, the underlying regulatory network of cell fate commitment during early neural differentiation remains elusive.\n\nResultsIn this study, we investigated the genome-wide transcriptome profile of single cells from six consecutive reprogramming and neural differentiation time points and identified cellular subpopulations present at each differentiation stage. Based on the inferred reconstructed trajectory and the characteristics of subpopulations contributing the most towards commitment to the central nervous system (CNS) lineage at each stage during differentiation, we identified putative novel transcription factors in regulating neural differentiation. In addition, we dissected the dynamics of chromatin accessibility at the neural differentiation stages and revealed active c/s-regulatory elements for transcription factors known to have a key role in neural differentiation as well as for those that we suggest are also involved. Further, communication network analysis demonstrated that cellular interactions most frequently occurred among embryoid body (EB) stage and each cell subpopulation possessed a distinctive spectrum of ligands and receptors associated with neural differentiation which could reflect the identity of each subpopulation.\n\nConclusionsOur study provides a comprehensive and integrative study of the transcriptomics and epigenetics of human early neural differentiation, which paves the way for a deeper understanding of the regulatory mechanisms driving the differentiation of the neural lineage.

developmental biology↗

Nitric oxide synthase-mediated early nitric oxide-burst alleviates drought-induced oxidative damage in ammonium supplied-rice roots

Ammonium (NH4+) can enhance rice drought tolerance in comparison to nitrate (NO3-). The mechanism underpinning this relationship was investigated based on the time-dependent nitric oxide (NO) production and its protective role in oxidative stress of NH4+-/NO3--supplied rice under drought. An early burst of NO was induced by drought 3h after root NH4+ treatment but not after NO3- treatment. Root oxidative damage induced by drought was significantly higher in NO3- than in NH4+-treatment due to its reactive oxygen species accumulation. Inducing NO production by applying NO donor 3h after NO3- treatment alleviated the oxidative damage, while inhibiting the early NO burst increased root oxidative damage in NH4+ treatment. Application of nitric oxide synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) completely suppressed NO synthesis in roots 3h after NH4+ treatment and aggravated drought-induced oxidative damage, indicating the aggravation of oxidative damage might have resulted from changes in NOS-mediated early NO burst. Drought also increased root antioxidant enzymes activities, which were further induced by NO donor but repressed by NO scavenger and NOS inhibitor in NH4+-treated roots. Thus, the NOS-mediated early NO burst plays an important role in alleviating oxidative damage induced by drought by enhancing antioxidant defenses in NH4+-supplied rice roots.\n\nHighlightNOS-mediated early NO burst plays an important role in alleviating oxidative damage induced by water stress, by enhancing the antioxidant defenses in roots supplemented with NH4+

physiology↗

Absence of GdX/UBL4A protects against inflammatory bowel diseases by regulating NF-κB signaling in DCs and macrophages

Nuclear factor-kappa B (NF-{kappa}B) activation is critical for innate immune responses. Here we report that the UBL4A (Ubiquitin-like protein 4A, also named GdX) enhances dendritic cells (DCs) and macrophages (M{varphi})-mediated innate immune defenses by positively regulating NF-{kappa}B signaling. GdX-deficient mice were resistant to LPS-induced endotoxin shock and DSS-induced colitis. DC- or M{varphi}-specific GdX-deficient mice displayed alleviated mucosal inflammation, and the production of pro-inflammatory cytokines by GdX-deficient DCs and M{varphi} was reduced. Mechanistically, we found that PTPN2 (TC45) and PP2A form a complex with RelA (p65) to mediate its dephosphorylation whereas GdX interrupts the TC45/PP2A/p65 complex formation and restrict p65 dephosphorylation by trapping TC45. Our study provides a mechanism by which NF-{kappa}B signaling is positively regulated by an adaptor protein GdX in DC or M{varphi} to maintain the innate immune response. Targeting GdX could be a strategy to reduce over-activated immune response in inflammatory diseases.

immunology↗

Development of reduced gluten wheat enabled by determination of the genetic basis of the lys3a low hordein barley mutant

Celiac disease is the most common food-induced enteropathy in humans with a prevalence of approximately 1% world-wide [1]. It is induced by digestion-resistant, proline- and glutamine-rich seed storage proteins, collectively referred to as \"gluten,\" found in wheat. Related prolamins are present in barley and rye. Both celiac disease and a related condition called non-celiac gluten sensitivity (NCGS) are increasing in incidence [2] [3]. This has prompted efforts to identify methods of lowering gluten in wheat, one of the most important cereal crops. Here we used BSR-seq (Bulked Segregant RNA-seq) and map-based cloning to identify the genetic lesion underlying a recessive, low prolamin mutation (lys3a) in diploid barley. We confirmed the mutant identity by complementing the lys3a mutant with a transgenic copy of the wild type barley gene and then used TILLING (Targeting Induced Local Lesions in Genomes) [4] to identify induced SNPs (Single Nucleotide Polymorphisms) in the three homoeologs of the corresponding wheat gene. Combining inactivating mutations in the three sub-genomes of hexaploid bread wheat in a single wheat line lowered gliadin and low molecular weight glutenin accumulation by 50-60% and increased free and protein-bound lysine by 33%. This is the first report of the combination of mutations in homoeologs of a single gene that reduces gluten in wheat.

plant biology↗

Cofilin-actin rod formation in neuronal processes after brain ischemia

Functional impairment after brain ischemia results in part from loss of neuronal spines and dendrites, independent of neuronal death. Cofilin-actin rods are covalently linked aggregates of colfilin-1 and actin that form in neuronal processes (neurites) under conditions of ATP depletion and oxidative stress, and which cause neurite degeneration if not disassembled. ATP depletion and oxidative stress occur with differing severity, duration, and time course in different ischemic conditions. Here we evaluated four mouse models of brain ischemia to define the conditions that drive formation of cofilin-actin rods. Three of the models provide early reperfusion: transient middle cerebral artery occlusion (MCAo), transient bilateral common carotid occlusion (CCAo), and cardiac arrest / cardiopulmonary resuscitation (CA/CPR). Early reperfusion restores ATP generating capacity, but also induces oxidative stress. The fourth model, photothrombotic cortical infarction, does not provide reperfusion. Cofilin-actin rods were formed in each of these models, but with differing patterns. Where acute reperfusion occurred, rod formation was maximal within 4 hours after reperfusion. Where infarction occurred, rods continued to form for at least 24 hours after ischemic onset, and extended into the adjacent non-ischemic tissue. Interventions that limit cofilin-actin rod formation may help to preserve integrity of neuronal processes in permanent ischemia.

neuroscience↗

Integrating genotype and weather variables for soybean yield prediction using deep learning

Realized performance of complex traits is dependent on both genetic and environmental factors, which can be difficult to dissect due to the requirement for multiple replications of many genotypes in diverse environmental conditions. To mediate these problems, we present a machine learning framework in soybean (Glycine max (L.) Merr.) to analyze historical performance records from Uniform Soybean Tests (UST) in North America, with an aim to dissect and predict genotype response in multiple envrionments leveraging pedigree and genomic relatedness measures along with weekly weather parameters. The ML framework of Long Short Term Memory - Recurrent Neural Networks works by isolating key weather events and genetic interactions which affect yield, seed oil, seed protein and maturity enabling prediction of genotypic responses in unseen environments. This approach presents an exciting avenue for genotype x environment studies and enables prediction based systems. Our approaches can be applied in plant breeding programs with multi-environment and multi-genotype data, to identify superior genotypes through selection for commercial release as well as for determining ideal locations for efficient performance testing.

bioinformatics↗

Pleotropic effects of PPARD accelerate colorectal tumor progression and invasion

Colorectal carcinogenesis (CRC) progression requires additional molecular mechanisms to APC mutations/aberrant {beta}-catenin signaling. PPARD is a druggable ligand-activated nuclear receptor that regulates essential genes involved in cell fate. PPARD is upregulated in intestinal epithelial cells (IECs) of human colorectal adenomas and adenocarcinomas. The mechanistic significance of PPARD upregulation in CRC remains unknown. Here we show that targeted PPARD overexpression in IECs of mice strongly augmented {beta}-catenin activation via BMP7/TAK1 signaling, promoted intestinal tumorigenesis in Apcmin mice, and accelerated CRC progression and invasiveness in mice with IEC-targeted Apc{Delta}580 mutation. Human CRC invasive fronts had higher PPARD expression than their paired adenomas. A PPARD agonist (GW501516) enhanced APC{Delta}580 mutation-driven CRC, while a PPARD antagonist (GSK3787) suppressed it. Functional proteomics analyses and subsequent validation studies uncovered PPARD upregulation of multiple pro-invasive pathways that drive CRC progression (e.g. PDGFR{beta}, AKT1, CDK1 and EIF4G1). Our results identify novel mechanisms by which PPARD promotes CRC invasiveness and provide the rational for the development of PPARD antagonists to suppress CRC.

cancer biology↗

Deconvolution of single-cell multi-omics layers reveals regulatory heterogeneity

Integrative analysis of multi-omics layers at single cell level is critical for accurate dissection of cell-to-cell variation within certain cell populations. Here we report scCAT-seq, a technique for simultaneously assaying chromatin accessibility and the transcriptome within the same single cell. We show that the combined single cell signatures enable accurate construction of regulatory relationships between cis-regulatory elements and the target genes at single-cell resolution, providing a new dimension of features that helps direct discovery of regulatory patterns specific to distinct cell identities. Moreover, we generated the first single cell integrated maps of chromatin accessibility and transcriptome in human pre-implantation embryos and demonstrated the robustness of scCAT-seq in the precise dissection of master transcription factors in cells of distinct states during embryo development. The ability to obtain these two layers of omics data will help provide more accurate definitions of \"single cell state\" and enable the deconvolution of regulatory heterogeneity from complex cell populations.

genomics↗