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Biology subjects

Xia, X.

Publications and source records attributed to Xia, X..

At least 73 records · Page 4Linked to original sources

RealSeq2: a software integrated with UMI identification, error correction, and methylation modifications storing

High-throughput UMI technology sequencing is widely used in early tumor screening, detection, recurrence monitoring, etc. Detecting extremely low-frequency mutations is especially important for monitoring tumor recurrence, so high-precision data, as well as high-quality data, are required. We developed RealSeq2, a new integrated data-preprocessing software based on fastp and gencore, to achieve adapter removal, quality control, UMI identification, and generate consensus reads by clustering and error correction using multithreading in high-throughput next-generation sequencing background. RealSeq2 also supports methylation data of 5-methylcytosine bisulfite-free sequencing. RealSeq2 defined a new tag in SAM for storing methylation information, which is beneficial for co-identifying methylation sites and mutation sites for downstream analysis. RealSeq2 includes three submodules: ReadsProfiler, ReadsCleaner, and ReadsRecycler. In addition, the output format file (BAM or SAM) is universal for downstream analyses. RealSeq2 is the preferred upstream analysis software for the co-detection of ultra-low frequency mutations and bisulfite-free methylation data. The error profile provides data support for downstream analysis. Additionally, XM tags will become a standard protocol for recording methylation signals.

bioinformatics↗

E2F1 Mediates SOX17 Deficiency-Induced Pulmonary Hypertension

RationaleRare genetic variants and genetic variation at loci in an enhancer in SRY-Box Transcription Factor 17 (SOX17) are identified in patients with idiopathic pulmonary arterial hypertension (PAH) and PAH with congenital heart disease. However, the exact role of genetic variants or mutation in SOX17 in PAH pathogenesis has not been reported. ObjectivesTo investigate the role of SOX17 deficiency in pulmonary hypertension (PH) development. MethodsHuman lung tissue and endothelial cells (ECs) from IPAH patients were used to determine the expression of SOX17. Tie2Cre-mediated and EC-specific deletion of Sox17 mice were assessed for PH development. Single-cell RNA sequencing analysis, human lung ECs, and smooth muscle cell culture were performed to determine the role and mechanisms of SOX17 deficiency. A pharmacological approach was used in Sox17 deficiency mice for therapeutic implication. Measurement and Main ResultsSOX17 expression was downregulated in the lungs and pulmonary ECs of IPAH patients. Mice with Tie2Cre mediated Sox17 knockdown and EC-specific Sox17 deletion developed spontaneously mild PH. Loss of endothelial Sox17 in EC exacerbated hypoxia-induced PH in mice. Loss of SOX17 in lung ECs induced endothelial dysfunctions including upregulation of cell cycle programming, proliferative and anti-apoptotic phenotypes, augmentation of paracrine effect on pulmonary arterial smooth muscle cells, impaired cellular junction, and BMP signaling. E2F Transcription Factor 1 (E2F1) signaling was shown to mediate the SOX17 deficiency-induced EC dysfunction and PH development. ConclusionsOur study demonstrated that endothelial SOX17 deficiency induces PH through E2F1 and targeting E2F1 signaling represents a promising approach in PAH patients.

physiology↗

Decoding CRISPR-Cas9 PAM recognition with UniDesign

The critical first step in CRISPR-Cas mediated gene editing is recognizing a preferred protospacer adjacent motif (PAM) on target DNAs by the proteins PAM-interacting amino acids (PIAAs). Thus, accurate computational modeling of PAM recognition is useful in assisting CRISPR-Cas engineering to relax or tighten PAM requirement for subsequence applications. Here we describe a universal computational protein design framework (UniDesign) for designing protein-nucleic acid interactions. As a proof of concept, we applied UniDesign to decode the PAM-PIAA interactions for eight Cas9 proteins. We show that, given native PIAAs, the UniDesign-predicted PAMs are largely identical to the natural PAMs of all Cas9s. In turn, given natural PAMs, the computationally redesigned PIAA residues largely recapitulated the native PIAAs (>70% and >80% in terms of identity and similarity, respectively). These results demonstrate that UniDesign faithfully captures the mutual preference between natural PAMs and native PIAAs, suggesting it as a useful tool for engineering CRISPR-Cas and other nucleic acid-interacting proteins. UniDesign is open-sourced at https://github.com/tommyhuangthu/UniDesign.

bioinformatics↗

Individual-specific functional connectivity shows improved performance in detecting and predicting individualized symptoms of Alzheimer's disease in elderly people with/without APOE ε4 allele

To date, no reliable biomarkers are available that link individual-specific functional connectivity and patients individualized symptoms for early detection and prediction of Alzheimers disease (AD) in elderly people with specific genotypes. Meanwhile, functional magnetic resonance imaging (MRI) and machine learning are promising tools that can reveal the relationships between brain and behavior at individual level towards predicting the transition to AD. In this study, individual-specific functional connectivity was constructed in elderly participants with Apolipoprotein E (APOE) {varepsilon}4 allele (N = 120) and without APOE {varepsilon}4 allele (N = 115), respectively. In particular, machine learning based on a recursive feature selection technique was carried out to track multiple clinical symptoms among differing genotypes at individual level from normal aging (NA) and AD. It was found that the captured neuroimaging features in both APOE genotyping groups were able to distinguish the changes of clinical symptoms from NA to AD. Besides, our findings illustrated that the connections between individual-specific functional regions exhibited significantly higher correlation between estimated and observed scores in multiple clinical symptoms than those from atlas-based functional connectivity for both APOE genotyping groups, while no significant performance was detected when the data of two APOE genotyping groups were combined for the estimation models. Further, individual-specific between-network connectivity constitutes a major contributor for accessing cognitive symptoms in both APOE genotyping groups. Therefore, this study demonstrated the essential role of individual variation in cortical functional anatomy and the significance in combining brain and behavior for improving the accuracy in detection and prediction of AD in elderly people with specific genotypes.

neuroscience↗

Targeted Protein Degradation via Nanoparticles

Strategies that hijack selective proteins of interest (POIs) to the intracellular protein recycling machinery for targeted protein degradation (TPD) have recently emerged as powerful tools for undruggable targets in biomedical research and the pharmaceutical industry. However, targeting any new POI with current TPD tools requires laborious case-by-case design for different diseases and cell types, especially for those extracellular targets. Here, we observed that nanoparticles (NPs) can mediate the receptor-free internalization of hijacked protein and further developed a generic paradigm for both intra- and extracellular POI degradation, by making full use of clinically approved components. The phenomenon is general, as we found nanostructures such as lipid nanoparticle (LNP), liposomes, exosomes, polymeric nanoparticles, inorganic nanoparticles and their hybrid nanoparticles modified with POI-recognizing moiety (antibody, peptides, small molecule drugs) can mediate TPD for a wide range of extracellular/membrane and intracellular targets. The super flexible and feasible-to-synthesize TPD-NPs paradigm may revolutionize the current TPD tools development landscape and it provides fundamental knowledge to receptor mediated drug therapies. HighlightsO_LINanoparticle mediated targeted protein degradation (TPD-NP) can be constructed by "Mix-and-Match" and do not require de novo synthesis or specific internalization design. C_LIO_LITPD-NPs can be equipped with specific cell type targeting capacity, loading and controlled release of therapeutic cargos, as well as biological barrier penetration capacity. C_LIO_LIAssembling components can be clinical-approved or biodegradable for translational medicine. C_LIO_LITPD-NP highly boosted current application platforms of nano-delivery and TPD. C_LI

bioengineering↗

Optimization and redevelopment of single-cell data analysis workflow based on deep generative models

The present single-cell RNA sequencing(scRNA-seq) analysis pipelines require a combination of appropriate normalization, dimension reduction, clustering, and specific-gene analysis algorithms, but the rationale for the choice of these algorithms is relatively subjective because of the lack of ground truth assessment conclusions. As the number of captured single-cells increases, the number of different types of noise cells also increases, which can strongly affect the analysis efficiency. For scRNA-seq, a technology that generates data through multi-process operations, the deep generative model should be a good choice for this type of data analysis, allowing simultaneous estimation of multiple unobservable parameters assumed in the data generation process. Hence, in our study, we sequenced a pool of pre-labeled single cells to obtain a batch of scRNA-seq data with main and fine labels, which was then used to evaluate the clustering and specific-gene analysis methods. Afterward, we applied two deep generative models to infer the probabilities of pseudo and impurity cells. And by stepwise removing the inferred noise cells, the clustering performance and the consistency of different specific-gene analysis methods are both greatly improved. After that, we applied Deep-LDA (a latent Dirichlet allocation-based deep generative model) to scRNA-seq data analysis. And this model takes the count matrix as input, and makes the classification and specific gene optimization process mutually dependent, which has more practical sense and simplifies the analysis workflow. At last, we successfully implemented the model with transferred knowledge to make single-cell annotation and verified its superior performance.

bioinformatics↗

Nardilysin-Regulated Scission Mechanism Activates Polo-like Kinase 3 to Suppress the Development of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) develops through step-wise genetic and molecular alterations including Kras mutation and inactivation of apoptotic pathways. Here, we find that development of anoikis resistance and metastasis of KrasG12D-driven PDAC in mice is accelerated by deleting Plk3, explaining the often reduced Plk3 expression in human PDAC. Importantly, a 41 kDa Plk3 (p41Plk3) that contained the entire kinase domain at the N-terminus (1-353 aa) is activated by scission of the precursor p72Plk3 at Arg354 by metalloendopeptidase Nardilysin (NRDC), and the resulting p32Plk3 C-terminal Polo-box domain (PBD) was quickly removed by proteasome degradation preventing the p41Plk3 inhibition by PBD. We found that p41Plk3 is the activated form of Plk3 that regulates a feedforward mechanism to promote anoikis and suppress PDAC and metastasis. p41Plk3 phosphorylates c-Fos on Thr164, which in turn, induces expression of Plk3 and pro-apoptotic genes. These findings uncovered an NRDC-regulated post-translational mechanism (PTM) that activates Plk3, establishing a prototypic regulation by scission mechanism.

cancer biology↗

An autoactive NB-LRR gene causes Rht13 dwarfism in wheat

Semidwarfing genes have greatly increased wheat yields globally, yet the widely used gibberellin (GA) insensitive genes Rht-B1b and Rht-D1b have disadvantages for seedling emergence. Use of the GA sensitive semidwarfing gene Rht13 avoids this pleiotropic effect. Here we show that Rht13 encodes a nucleotide-binding site/leucine-rich repeat (NB-LRR) gene. A point mutation in the semidwarf Rht-B13b allele autoactivates the NB-LRR gene and causes a height reduction comparable to Rht-B1b and Rht-D1b in diverse genetic backgrounds. The autoactive Rht-B13b allele leads to transcriptional upregulation of pathogenesis-related genes including class III peroxidases associated with cell wall remodelling. Rht13 represents a new class of reduced height (Rht) gene, unlike other Rht genes which encode components of the GA signalling or metabolic pathways. This discovery opens new avenues to use autoactive NB-LRR genes as semidwarfing genes in a range of crop species, and to apply Rht13 in wheat breeding programmes using a perfect genetic marker.

plant biology↗

Urine-derived exosomes from individuals with IPF carry pro-fibrotic cargo.

BackgroundMicroRNAs (miRNA) and other components contained in extracellular vesicles may reflect the presence of a disease. Lung tissue, sputum and sera of individuals with idiopathic pulmonary fibrosis (IPF) show alterations in miRNA expression. We designed this study to test whether urine and/or tissue derived exosomal miRNAs from individuals with IPF carry cargo that can promote fibrosis. MethodsExosomes were isolated from urine (U-IPFexo), lung tissue myofibroblasts (MF-IPFexo), serum from individuals with IPF (n=16) and age/sex-matched controls without lung disease (n=10). We analyzed microRNA expression of isolated exosomes and their in vivo bio-distribution. We investigated the effect on ex vivo skin wound healing and in in vivo mouse lung models. ResultsU-IPFexo or MF-IPFexo expressed miR let-7d, miR-29a-5p, miR 181b-3p and miR-199a-3p consistent with previous reports of miRNA expression obtained from lung tissue/sera from patients with IPF. In vivo bio-distribution experiments detected bioluminescent exosomes in the lung of normal C57Bl6 mice within 5 minutes after intravenous infusion, followed by distribution to other organs irrespective of exosome source. Exosomes labeled with gold nanoparticles and imaged by transmission electron microscopy were visualized in alveolar epithelial type I and type II cells. Treatment of human and mouse lung punches obtained from control, non-fibrotic lungs with either U-IPFexo or MF-IPFexo produced a fibrotic phenotype. A fibrotic phenotype was also induced in a human ex vivo skin model and in in vivo lung models. ConclusionsOur results provide evidence of a systemic feature of IPF whereby exosomes contain pro-fibrotic miRNAs when obtained from a fibrotic source and interfere with response to tissue injury as measured in skin and lung models. FundingThis work was supported in part by Lester and Sue Smith Foundation and The Samrick Family Foundation and NIH grants R21 AG060338 (SE and MKG), U01 DK119085 (IP, RS, MTC).

cell biology↗

Structures and comparison of endogenous 2-oxoglutarate and pyruvate dehydrogenase complexes from bovine kidney

The -keto acid dehydrogenase complex family catalyzes the essential oxidative decarboxylation of -keto acids to yield acyl-CoA and NADH. Despite performing the same overarching reaction, members of the family have different component structures and structural organization between each other and across phylogenetic species. While native structures of -keto acid dehydrogenase complexes from bacteria and fungi became available recently, the atomic structure and organization of their mammalian counterparts in their native states remain unknown. Here, we report the cryo electron microscopy (cryoEM) structures of the endogenous cubic 2-oxoglutarate dehydrogenase complex (OGDC) and icosahedral pyruvate dehydrogenase complex (PDC) cores from bovine kidney determined at 3.5 [A] and 3.8 [A] resolution, respectively. The structures of multiple protein were reconstructed from a single lysate sample, allowing direct structural comparison without the concerns of differences arising from sample preparation and structure determination. Although native and recombinant E2 core scaffold structures are similar, native structures are decorated with their peripheral E1 and E3 subunits. Asymmetric sub-particle reconstructions support heterogeneity in the arrangements of these peripheral subunits. Additionally, despite sharing a similar monomeric fold, OGDC and PDC E2 cores have distinct interdomain and intertrimer interactions, which suggests a means of modulating self-assembly to mitigate heterologous binding between mismatched E2 species. The lipoyl moiety lies near a mobile gatekeeper within the interdomain active site of OGDC E2 and PDC E2. Analysis of the two-fold related intertrimer interface identified secondary structural differences and chemical interactions between icosahedral and cubic geometries of the core. Taken together, our study provides direct structural comparison of OGDC and PDC from the same source and offers new insights into determinants of interdomain interactions and of architecture diversity among -keto acid dehydrogenase complexes.

molecular biology↗

Local 5-HT signal bi-directionally regulates the coincidence time window of associative learning

Temporal coincidence between the conditioned stimulus (CS) and unconditioned stimulus (US) is essential for associative learning across species. Despite its ubiquitous presence, the mechanism that may regulate this time window duration remains unclear yet. Using olfactory associative learning in Drosophila as a model, we find that suppressing or promoting serotonin (5-HT) signal could respectively shorten or prolong the coincidence time window of odor-shock associative learning and synaptic plasticity in mushroom body (MB) Kenyon cells (KCs). Capitalizing on GPCR-activation based (GRAB) sensors for 5-HT and acetylcholine (ACh), we characterized the in vivo 5-HT dynamics in MB lobes during odor and shock stimulations and further dissected this microcircuit. Interestingly, local KC-released ACh activates nicotinic receptors on the dorsal paired medial (DPM) neuron, and in turn the DPM neuron releases 5-HT to inhibit the ACh signal via the 5-HT1a receptor. Finally, we demonstrated that the DPM-mediated serotonergic feedback circuit is sufficient and necessary to regulate the coincidence time window. This work provides a model for studying the temporal contingency of environmental events and their causal relationship.

neuroscience↗

Comparative thermophysiology of marine Synechococcus CRD1 strains isolated from different thermal niches in iron-depleted areas

Marine Synechococcus cyanobacteria are ubiquitous in the ocean, a feature likely related to their extensive genetic diversity. Amongst the major lineages, clades I and IV preferentially thrive in temperate and cold, nutrient-rich waters, whilst clades II and III prefer warm, nitrogen or phosphorus-depleted waters. The existence of such cold (I/IV) and warm (II/III) thermotypes is corroborated by physiological characterization of representative strains. A fifth clade, CRD1, was recently shown to dominate the Synechococcus community in iron-depleted areas of the world ocean and to encompass three distinct ecologically significant taxonomic units (ESTUs CRD1A-C) occupying different thermal niches, suggesting that distinct thermotypes could also occur within this clade. Here, using comparative thermophysiology of strains representative of these three CRD1 ESTUs we show that the CRD1A strain MITS9220 is a warm thermotype, the CRD1B strain BIOS-U3-1 a cold temperate thermotype, and the CRD1C strain BIOS-E4-1 a warm temperate stenotherm. Curiously, the CRD1B thermotype lacks traits and/or genomic features typical of cold thermotypes. In contrast, we found specific physiological traits of the CRD1 strains compared to their clade I, II, III and IV counterparts, including a lower growth rate and photosystem II maximal quantum yield at most temperatures and a higher turnover rate of the D1 protein. Together, our data suggests that the CRD1 clade prioritizes adaptation to low-iron conditions over temperature adaptation, even though the occurrence of several CRD1 thermotypes likely explains why the CRD1 clade as a whole occupies most iron-limited waters.

microbiology↗

CLE42 Delays Leaf Senescence by Antagonizing Ethylene Pathway in Arabidopsis

Leaf senescence is the final stage of leaf development and is influenced by numerous internal and environmental factors. CLE family peptides are plant-specific peptide hormones that regulate various developmental processes. However, the role of CLE in regulating leaf senescence remains unclear. Here, we found that CLE42 is a negative regulator of leaf senescence by using a CRISPR/Cas9-produced CLE mutant collection. The cle42 mutant displayed earlier senescence phenotypes, while overexpression of CLE42 delayed age-dependent and dark-induced leaf senescence. Moreover, application of the synthesized 12-aa peptide (CLE42p) also delayed leaf senescence under natural and dark conditions. CLE42 and CLE41/44 displayed functional redundancy in leaf senescence, and the cle41 cle42 cle44 triple mutant displayed more pronounced earlier senescence phenotypes than any single mutant. Analysis of differentially expressed genes obtained by RNA-Seq methodology revealed that ethylene pathway was suppressed by overexpressing CLE42. Moreover, CLE42 suppressed ethylene biosynthesis and thus promoted the protein accumulation of EBF, which in turn decreased the function of EIN3. Accordingly, mutation of EIN3/EIL1 or overexpression of EBF1 suppressed the earlier senescence phenotypes of the cle42 mutant. Together, our results reveal that the CLE peptide hormone regulates leaf senescence by communicating with ethylene pathway.

plant biology↗

Structure, dynamics and assembly of the ankyrin complex on human red blood cell membrane

The cytoskeleton of red blood cell (RBC) is anchored to cell membrane by the ankyrin complex. This complex is assembled during RBC genesis and comprises primarily band 3, protein 4.2 and ankyrin, whose mutations contribute to numerous human inherited diseases. High-resolution structures of the ankyrin complex have been long sought-after to understand its assembly and disease-causing mutations. Here, we analyzed native complexes on human RBC membrane by stepwise fractionation. Cryo-electron microscopy structures of nine band 3-associated complexes reveal that protein 4.2 stabilizes the cytoplasmic domain of band 3 dimer. In turn, the superhelix-shaped ankyrin binds to this protein 4.2 via ankyrin repeats (ARs) 6-13 and to another band 3 dimer via ARs 17-20, bridging two band 3 dimers in the ankyrin complex. Integration of these structures with both prior and our biochemical data supports a model of ankyrin complex assembly during erythropoiesis and identifies interactions essential for mechanical stability of RBC.

biophysics↗

Tumor elimination by clustered microRNAs miR-306 and miR-79 via non-canonical activation of JNK signaling

JNK signaling plays a critical role in both tumor promotion and tumor suppression. Here, we identified clustered microRNAs (miRNAs) miR-306 and miR-79 as novel tumor-suppressor miRNAs that specifically eliminate JNK-activated tumors in Drosophila. While showing no significant effect on normal tissue growth, miR-306 and miR-79 strongly suppressed growth of multiple tumor models including malignant tumors caused by Ras activation and cell polarity defects. Mechanistically, these miRNAs commonly target the mRNA of an E3 ubiquitin ligase Drosophila ring finger protein 146 (dRNF146). We found that DRNF146 promotes degradation of tankyrase (Tnks), an ADP-ribose polymerase that promotes JNK activation in a non-canonical manner. Thus, downregulation of dRNF146 by miR-306 and miR-79 leads to hyper-enhancement of JNK activation. Our data show that, while JNK activity is essential for tumor growth, elevation of miR-306 or miR-79 overactivate JNK signaling to the lethal level via non-canonical JNK pathway and thus eliminate tumors, providing a new miRNA-based strategy against cancer.

cell biology↗

A Prism Vote Framework for Individualized Risk Prediction of Traits in Genome-wide Sequencing Data of Multiple Populations

Multi-population cohorts offer unprecedented opportunities for profiling disease risk in large samples, however, heterogeneous risk effects underlying complex traits across populations make integrative prediction challenging. In this study, we propose a novel Bayesian probability framework, the Prism Vote (PV), to construct risk predictions in heterogeneous genetic data. The PV views the trait of an individual as a composite risk from subpopulations, in which stratum-specific predictors can be formed in data of more homogeneous genetic structure. Since each individual is represented by a composition of subpopulation memberships, the framework enables individualized risk characterization. Simulations demonstrated that the PV framework applied with alternative prediction methods significantly improved prediction accuracy in mixed and admixed populations. The advantage of PV enlarges as the sample size, genetic heterogeneity, and population diversity increase. In two real genome-wide association data consists of multiple populations, we showed that the framework enhanced prediction accuracy of the linear mixed model by up to 12.1% in five-group cross validations. The proposed framework offers a new aspect to analyze individuals disease risk and improve accuracy for predicting complex traits in genome data.

genetics↗

FOXP4 differentially controls cold-induced beige adipocyte differentiation and thermogenesis

Beige adipocytes possess a discrete developmental origin and notable plasticity in thermogenic capacity in response to various environmental cues. But the transcriptional machinery controlling beige adipocyte development and thermogenesis remains largely unknown. By analyzing beige adipocyte-specific knockout mice, we identified a transcription factor, Forkhead Box P4 (FOXP4) that differentially governs beige adipocyte differentiation and activation. Depletion of Foxp4 caused a decline in the frequency of beige preadipocytes by switching their cell fate towards fibroblastic cells at the expense of beige adipocytes. However, we observed that ablation of Foxp4 in differentiated adipocytes profoundly potentiated their thermogenesis upon cold exposure. Of note, the outcome of Foxp4-deficiency on UCP1-mediated thermogenesis was confined to beige adipocytes, rather than to brown adipocytes. Taken together, we submit that FOXP4 primes beige adipocyte cell fate commitment and differentiation by potent transcriptional repression of the thermogenic program.

cell biology↗

Cardiotoxic effects of methamphetamine associated with electrophysiological and epigenetic aberrations in Zebrafish

Long-term methamphetamine (Meth) abuse damages functional and molecular changes in the brain that causes chronic and relapsing disease. In this study, we sought to investigate a relationship between cardiotoxicity and arrhythmia with associated Meth abuse in zebrafish to identify and to understand the adverse cardiac symptoms associated with Meth as well as to assess the applicability of zebrafish as an appropriate model for cardiac-related drug screening studies. Over a two-week duration, zebrafish were first treated with various concentrations of Meth, ranging from 0 to 50 M. Immediately after treatment, zebrafish underwent electrocardiogram (ECG) measurement for electrophysiological analysis. Results show that a higher incidence of increased heart rate over the duration of the experiment, corroborating with results from previous human case studies involving Meth users. However, abnormalities commonly cited in those same case studies, such as prolongation of QTc, were not significantly presented in obtained ECG recordings. We have also conducted genetic, epigenetic, and histochemical analysis in an attempt to understand the cardiotoxic effects of Meth on zebrafish cardiac function. These results suggested myocardial damage and decrease in gene expression associated with normal physiological function. Finally, this paper provides insights into potential reasons for the apparent discrepancies in our data with prior research as well as an outlook of zebrafish cardiotoxic drug screening studies.

physiology↗