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Wang, M.

Publications and source records attributed to Wang, M..

At least 847 records · Page 47Linked to original sources

ADAMTS-family protease MIG-17 regulates synaptic allometry by modifying the extracellular matrix and modulating glia morphology during growth

Synapses are largely established during embryogenesis and maintained during growth. The mechanisms that regulate synaptic allometry--the maintenance of synaptic positions during growth--are largely unknown. We performed forward genetic screens in C. elegans for synaptic allometry mutants and identified mig-17, a secreted metalloprotease of the conserved ADAMTS family. Through proteomic mass spectrometry analyses, cell biological and genetic studies we determined that MIG-17 is expressed by muscle cells to modulate glia location and morphology. Glia are proximal to synapses, and the glial location and morphology determine synaptic position during growth. Mig-17 regulates synapse allometry by influencing epidermal-glia crosstalk through the regulation of basement membrane proteins, including collagen type IV, SPARC and fibulin. Our findings underscore the importance of glia location in the maintenance of synaptic allometry, and uncover a muscle-epidermal-glia signaling axis, mediated through the extracellular matrix, in the regulation of glia morphology and synaptic positions during growth.

neuroscience↗

Widespread arginine phosphorylation in human cells - a novel protein PTM revealed by mass spectrometry

Arginine phosphorylation (pArg) is recently discovered as a ubiquitous protein N- phosphorylation in bacteria. However, its prevalence and roles in mammalian cells remain largely unknown due to the lack of established workflow and the inherent lability of the phosphoramidate (P-N) bond. Emerging evidence suggests that N-phosphorylation may extensively exist in eukaryotes and play crucial roles. We report an experimental phosphoproteomic workflow, which for the first time allowed to reveal the widespread occurrence of pArg in human cells by mass spectrometry. By virtue of this approach, we identified 152 high-confidence pArg sit]es derived from 118 proteins. Remarkably, the discovered phosphorylation motif and gene ontology of pArg hint a possible cellular function of arginine phosphorylation by regulating the favorability of propeptide convertase substrate. The generated extensive data set should enable a better understanding of the biological functions of eukaryotic pArg in the future.\n\n\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=37 SRC=\"FIGDIR/small/725291v1_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (13K):\norg.highwire.dtl.DTLVardef@77b2d0org.highwire.dtl.DTLVardef@7c76f4org.highwire.dtl.DTLVardef@1658d6borg.highwire.dtl.DTLVardef@27a2e2_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

Nrf1 is endowed with a dominant tumor-repressing effect onto the Wnt/β-Catenin-dependent and -independent signaling networks in the human liver cancer

Our previous work revealed that Nrf1 exerts a tumor-repressing effect because its genomic loss (to yield Nrf1-/-) results in oncogenic activation of Nrf2 and target genes. Interestingly, {beta}-catenin is concurrently activated by loss of Nrf1 in a way similar to {beta}-catenin-driven liver tumor. However, a presumable relationship between Nrf1 and {beta}-catenin is not as yet established. Here, we demonstrate that Nrf1 enhanced ubiquitination of {beta}-catenin for targeting to proteasomal degradation. Conversely, knockdown of Nrf1 by its short-hairpin RNA (shNrf1) caused accumulation of {beta}-catenin so as to translocate the nucleus, allowing activation of a subset of Wnt-{beta}-catenin signaling responsive genes, which leads to the epithelial-mesenchymal transition (EMT) and related cellular processes. Such silencing of Nrf1 resulted in malgrowth of human hepatocellular carcinoma, along with malignant invasion and metastasis to the lung and liver in xenograft model mice. Further transcriptomic sequencing unraveled significant differences in the expression of both Wnt/{beta}-catenin-dependent and -independent responsive genes implicated in the cell process, shape and behavior of the shNrf1-expressing tumor. Notably, we identified that {beta}-catenin is not a target gene of Nrf1, but this CNC-bZIP factor contributes to differential or opposing expression of other critical genes, such as CDH1, Wnt5A, Wnt11A, FZD10, LEF, TCF4, SMAD4, MMP9, PTEN, PI3K, JUN and p53, each of which depends on the positioning of distinct cis-regulatory sequences (e.g., ARE and/or AP-1 binding sites) in the gene promoter contexts. In addition, altered expression profiles of some Wnt-{beta}-catenin signaling proteins were context-dependent, as accompanied by decreased abundances of Nrf1 in the clinic human hepatomas with distinct differentiation. Together, these results corroborate the rationale that Nrf1 acts as a bona fide dominant tumor-repressor, by its intrinsic inhibition of Wnt-{beta}-catenin signaling and relevant independent networks in cancer development and malignant progression.

cancer biology↗

Essential role of Bone morphogenetic protein 15 in porcine ovarian and follicular development and ovulation

Bone morphogenetic protein 15 (BMP15) is a multifunctional oocyte-specific secreted factor. It controls female fertility and follicular development in both species-specific and dosage-sensitive manners. Previous studies found that BMP15 played a critical role on follicular development and ovulation rate of mono-ovulatory mammalian species, but has minimal impact on poly-ovulatory mice. However, whether this is true in non-rodent poly-ovulatory species need to be validated. To investigate this question, we generated a BMP15 knockdown pig model. We found that BMP15 knockdown gilts showed markedly reduced fertility accompanied with phenotype of dysplastic ovaries containing significantly declined number of follicles, increased number of abnormal follicles, and abnormally enlarged antral follicles resulting in disordered ovulation. Molecular and transcriptome analysis revealed that knockdown of BMP15 significantly suppressed cell proliferation, differentiation, Fshr expression, leading to premature luteinization and reduced estradiol production in GCs, and simultaneously decreased the quality and meiotic maturation of oocyte. Our results provide in vivo evidences for the essential role of BMP15 in porcine ovarian and follicular development, and new insight into the complicated regulatory function of BMP15 in female fertility of poly-ovulatory species.

developmental biology↗

CRMP2 mediates Sema3F-dependent axon pruning and dendritic spine remodeling

Regulation of axon guidance and pruning of inappropriate synapses by class 3 semaphorins is key to development of neural circuits. Collapsin response mediator protein 2 (CRMP2) has been shown to regulate axon guidance by mediating Semaphorin 3A (Sema3A) signaling and its dysfunction has been linked to schizophrenia, however, nothing is known about its role in the synapse pruning. Here, using newly generated crmp2-/- mice we demonstrate that while CRMP2 has only a moderate effect on Sema3A-dependent axon guidance in vivo, it is essential for Sema3F-dependent axon pruning and dendritic spine remodeling. We first demonstrate that CRMP2 deficiency interferes with Sema3A signaling in compartmentalized neuron cultures and leads to a mild defect in axon guidance in peripheral nerves and corpus callosum. Strikingly, we show that crmp2-/- mice display more prominent defects in dendritic spine pruning and stereotyped axon pruning in hippocampus and visual cortex consistent with impaired Sema3F signaling and with autism spectrum disorder (ASD)-rather than schizophrenia-like phenotype. Indeed, we demonstrate that CRMP2 mediates Sema3F-induced axon retraction in primary neurons and that crmp2-/- mice display early postnatal behavioral changes linked to ASD. In conclusion, we demonstrate that CRMP2 is an essential mediator of Sema3F-dependent synapse pruning and its dysfunction in early postnatal stages shares histological and behavioral features of ASD.

neuroscience↗

Cholesterol and matrisome pathways dysregulated in human APOE ε4 glia

Apolipoprotein E (APOE) {varepsilon}4 is the strongest genetic risk factor for Alzheimers disease (AD). Although its association with AD is well-established, the impact of APOE {varepsilon}4 on human brain cell function remains unclear. Here we investigated the effects of APOE {varepsilon}4 on several brain cell types derived from human induced pluripotent stem cells and human APOE targeted replacement mice. Gene set enrichment and pathway analyses of whole transcriptome profiles showed that APOE {varepsilon}4 is associated with dysregulation of cholesterol homeostasis in human but not mouse astrocytes and microglia. Elevated matrisome signaling associated with chemotaxis, glial activation and lipid biosynthesis in APOE {varepsilon}4 mixed neuron/astrocyte cultures parallels altered pathways uncovered in cell-type deconvoluted transcriptomic data from APOE {varepsilon}4 glia and AD post-mortem brains. Experimental validation of the transcriptomic findings showed that isogenic APOE {varepsilon}4 is associated with increased lysosomal cholesterol levels and decreased cholesterol efflux, demonstrating decoupled lipid metabolism. APOE {varepsilon}4 glia also secrete higher levels of proinflammatory chemokines, cytokines and growth factors, indicative of glial activation. Thus, APOE {varepsilon}4 induces human glia-specific dysregulation that may initiate AD risk.

neuroscience↗

Evolutionary Analysis of RNA Editing and Amino Acid Recoding in Cephalopods

RNA editing is a post-transcriptional modification process that alters nucleotides of mRNA and consequently the amino acids of the translated protein without changing the original DNA sequence. In human and other mammals, amino acid recoding from RNA editing is rare, and most edits are non-adaptive and provide no fitness advantage (1). However, recently it was discovered that in soft-bodied cephalopods, which are exceptionally intelligent and include squid, octopus, and cuttlefish, RNA editing is widespread and positively selected (2). To examine the effects of RNA editing on individual genes, we developed a \"diversity score\" system that quantitatively assesses the amount of diversity generated in each gene, incorporating combinatorial diversity and the radicalness of amino acid changes. Using this metric, we compiled a list of top 100 genes across the cephalopod species that are most diversified by RNA editing. This list of candidate genes provides directions for future research into the specific functional impact of RNA editing in terms of protein structure and cellular function on individual proteins. Additionally, considering the connection of RNA editing to the nervous system, and the exceptional intelligence of cephalopod, the candidate genes may shed light to the molecular development of behavioral complexity and intelligence. To further investigate global influences of RNA editing on the transcriptome, we investigated changes in nucleotide composition and codon usage biases in edited genes and coleoid transcriptome in general. Results show that these features indeed correlate with editing and may correspond to causes or effects of RNA editing. In addition, we characterized the unusual RNA editing in cephalopods by analyzing ratio of radical to conservative amino acid substitutions (R/C) and distribution of amino acid recoding from editing. Our results show that compared to model organisms, editing in cephalopods have significantly decreased R/C ratio and distinct distribution of amino acid substitutions that favor conservative over radical changes, indicating selection at the amino acid level and providing a potential mechanism for the evolution of widespread RNA editing in cephalopods.

evolutionary biology↗

Mechanistic Elucidation of the Antitumor Properties of a Novel Death Receptor 5 Activator

Disulfide bond Disrupting Agents (DDAs) are a new chemical class of agents recently shown to have activity against breast tumors in animal models. However, it is unknown how DDAs trigger cancer cell death without affecting nontransformed cells. As demonstrated here, DDAs are the first compounds identified that upregulate the TRAIL receptor DR5 through both transcriptional and posttranscriptional mechanisms. At the protein level, DDAs alter DR5 disulfide bonding to increase steady-state DR5 levels and oligomerization, leading to downstream Caspase 8 and 3 activation. DDAs and TRAIL synergize to kill cancer cells and are cytotoxic to HER2+ cancer cells with acquired resistance to the EGFR/HER2 tyrosine kinase inhibitor. Investigation of the mechanisms responsible for DDA selectivity for cancer cells reveals that DDA-induced upregulation of DR5 is enhanced in the context of EGFR overexpression, and DDA-induced cytotoxicity is strongly amplified by MYC overexpression. Together, the results demonstrate selective DDA lethality against oncogene-transformed cells, DDA-mediated DR5 upregulation and protein stabilization, and DDAs against drug-resistant and metastatic cancer cells. DDAs thus represent a new therapeutic approach to cancer therapy.

cancer biology↗

Dynamic brain network changes reflect neuroplasticity: molecular and cognitive evidence

Resting-state functional brain networks demonstrate dynamic changes on the scale of seconds. However, their genetic mechanisms and profound cognitive relevance remain less explored. We identified 459 Bonferroni-corrected genes, by associating temporal variability of regional functional connectivity patterns with Allen Brain gene expression profiles across the whole brain. These genes are partially verified in developing human brain gene expression in the BrainSpan Atlas, and are found to be involved in the enrichment of short- and long-term plasticity processes. The former process depends on synaptic plasticity, involving ion transmembrane transport, action potential propagation, and modulation. The latter process depends on structural plasticity, including axonal genesis, development, and guidance. Results from a longitudinal cognitive training study further revealed that baseline variability of the hippocampal network predicted cognitive ability changes after three months of training. Our genetic association results suggest that the short-term plasticity processes may account for the rapid changes of regional functional connectivity, while the underlying long-term plasticity processes explain why temporal variability can predict long-term learning outcomes. To our knowledge, this is the first demonstration that measuring the dynamic brain network can lead to a non-invasive quantification of neuroplasticity in humans.

neuroscience↗

Domain-centric dissection and classification of prokaryotic poly(3-hydroxyalkanoate) synthases

Although many enzymes and multiple pathways involve in Polyhydroxyalkanoates (PHAs) synthesis, PHA synthases play a determinant role in the process, which include three subunits of PhaC, PhaE, and PhaR. Currently, PHA synthases are categorized into four classes according to its primary sequences, substrate specificity, and subunit composition. However, theoretical analysis of PHA synthases from the domain perspective has not been performed. In this study, we dissected PHA synthases thoroughly through analysis of domain organization. Both referenced bacterial and archaeal proteomes were then screened for the presence and absence of different PHA synthases along NCBI taxonomy ID-based phylogenetic tree. In addition, sequences annotated as bacterial and archaeal PhaCs in UniProt database were also analyzed for domain organizations and interactions. In sum, the in-silico study provided a better understanding of the domain features of PHA synthases in prokaryotes, which also assisted in the production of PHA polymers with optimized chemical properties.

genomics↗

Vascularized human cortical organoids model cortical development in vivo

Modelling the neuronal progenitor proliferation and organization processes that produce mature cortical neuron subtypes is essential for the study of human brain development and the search for potential cell therapies. To provide a vascularized and functional model of brain organoids, we demonstrated a new paradigm to generate vascularized organoids that consist of typical human cortical cell types and recapitulate the lamination of the neocortex with a vascular structure formation for over 200 days. In addition, the observation of the sEPSCs (spontaneous Excitatory Postsynaptic Potential) and sIPSCs (spontaneous Inhibitory Postsynaptic Potential) and the bidirectional electrical transmission indicated the presence of chemical and electrical synapses in the vOrganoids. More importantly, the single-cell RNA-seq analysis illustrated that the vOrganoids exhibited microenvironments to promote neurogenesis and neuronal maturation that resembled in vivo processes. The transplantation of the vOrganoids to the mouse S1 cortex showed human-mouse co-constructed functional blood vessels in the grafts that could promote the survival and integration of the transplanted cells to the host. This vOrganoid culture method could not only serve as a model to study human cortical development and to explore brain disease pathology but could also provide potential prospects for new cell therapies for neural system disorders and injury.

neuroscience↗

A revised 1.6 Å structure of the GTPase domain of the Parkinson’s disease-associated protein LRRK2 provides insights into mechanisms

Leucine-rich repeat kinase 2 (LRRK2) is a large 286 kDa multi-domain protein whose mutation is a common cause of Parkinsons disease (PD). One of the common sites of familial PD-associated mutations occurs at residue Arg-1441 in the GTPase domain of LRRK2. Previously, we reported that the PD-associated mutation R1441H impairs the catalytic activity of the GTPase domain thereby traps it in a persistently \"on\" state. More recently, we reported that the GTPase domain of LRRK2 exists in a dynamic dimer-monomer equilibrium where GTP binding shifts it to the monomeric conformation while GDP binding shifts it back to the dimeric state. We also reported that all of the PD-associated mutations at Arg-1441, including R1441H, R1441C, and R1441G, impair the nucleotide-dependent dimer-monomer conformational dynamics of the GTPase domain. However, the mechanism of this nucleotide-dependent conformational dynamics and how it is impaired by the mutations at residue Arg-1441 remained unclear. Here, we report a 1.6 [A] crystal structure of the GTPase domain of LRRK2. Our structure has revealed a dynamic switch region that can be differentially regulated by GTP and GDP binding. This nucleotide-dependent regulation is impaired when residue Arg-1441 is substituted with the PD-associated mutations due to the loss of its exquisite interactions consisting of two hydrogen bonds and a {pi}-stacking interaction at the dimer interface.\n\nSignificance StatementMutations in LRRK2 are associated with familial Parkinsons disease, so understanding its mechanism of actions and how they are changed by the disease-associated mutations is important for developing therapeutic strategies. This paper describes an atomic structure of the G-domain of LRRK2 revealing that the conformational dynamics of the switch regions are potentially important for its normal function. It further shows that a disease-associated mutation could lock the G domain in a persistently active-like conformation, thus perturbing its normal function.

biochemistry↗

CD49f is a novel marker to purify functional human iPSC-derived astrocytes

Astrocytes play a central role in the central nervous system (CNS), maintaining brain homeostasis, providing metabolic support to neurons, regulating connectivity of neural circuits, and controlling blood flow as an integral part of the blood-brain barrier. They have been increasingly implicated in the mechanisms of neurodegenerative diseases, prompting a greater need for methods that enable their study. The advent of human induced pluripotent stem cell (iPSC) technology has made it possible to generate patient-specific astrocytes and CNS cells using protocols developed by our team and others as valuable disease models. Yet isolating astrocytes from primary specimens or from in vitro mixed cultures for downstream analyses has remained challenging. To address this need, we performed a screen for surface markers that allow FACS sorting of astrocytes. Here we demonstrate that CD49f is an effective marker for sorting functional human astrocytes. We sorted CD49f+ cells from a protocol we previously developed that generates a complex culture of oligodendrocytes, neurons and astrocytes from iPSCs. CD49f+-purified cells express all canonical astrocyte markers and perform characteristic functions, such as neuronal support and glutamate uptake. Of particular relevance to neurodegenerative diseases, CD49f+ astrocytes can be stimulated to take on an A1 neurotoxic phenotype, in which they secrete pro-inflammatory cytokines and show an impaired ability to support neuronal maturation. This study establishes a novel marker for isolating functional astrocytes from complex CNS cell populations, strengthening the use of iPSC-astrocytes for the study of their regulation and dysregulation in neurodegenerative diseases.

neuroscience↗

The Molecular and Microbial Microenvironments in Chronically Diseased Lungs

To visualize the personalized distributions of pathogens, chemical environments including microbial metabolites, pharmaceuticals, and their metabolic products within and between human lungs afflicted with cystic fibrosis, we generated 3D microbiome and metabolome maps of six explanted lungs from three cystic fibrosis patients. These 3D spatial maps revealed that the chemical environments are variable between patients and within the lungs of each patient. Although the patients microbial ecosystems were defined by the dominant pathogen, their chemical diversity was not. Additionally, the chemical diversity between locales in lungs of the same individual sometimes exceeded inter-individual variation. Thus, the chemistry and microbiome of the explanted lungs appear to be not only personalized but also regiospecific. Previously undescribed analogs of microbial quinolones and antibiotic metabolites were also detected. Furthermore, mapping the chemical and microbial distributions allowed visualization of microbial community interactions, such as increased production of quorum sensing quinolones in locations where Pseudomonas was in contact with Staphylococcus and Granulicatella, consistent with in vitro observations of bacteria isolated from these patients. Visualization of microbe-metabolite associations within a host organ in early-stage CF disease in animal models will help elucidate a complex interplay between the presence of a given microbial structure, antibiotics, metabolism of antibiotics, microbial virulence factors, and host responses.\n\nImportanceMicrobial infections are now recognized to be polymicrobial and personalized in nature. A comprehensive analysis and understanding of the factors underlying the polymicrobial and personalized nature of infections remains limited, especially in the context of the host. By visualizing microbiomes and metabolomes of diseased human lungs, we describe how different the chemical environments are between hosts that are dominated by the same pathogen and how community interactions shape the chemical environment, or vice versa. We highlight that three-dimensional organ mapping are hypothesis building tools that allow us to design mechanistic studies aimed at addressing microbial responses to other microbes, the host, and pharmaceutical drugs.

microbiology↗

Chemical Impacts of the Microbiome Across Scales Reveal Novel Conjugated Bile Acids

A mosaic of cross-phyla chemical interactions occurs between all metazoans and their microbiomes. In humans, the gut harbors the heaviest microbial load, but many organs, particularly those with a mucosal surface, associate with highly adapted and evolved microbial consortia1. The microbial residents within these organ systems are increasingly well characterized, yielding a good understanding of human microbiome composition, but we have yet to elucidate the full chemical impact the microbiome exerts on an animal and the breadth of the chemical diversity it contributes2. A number of molecular families are known to be shaped by the microbiome including short-chain fatty acids, indoles, aromatic amino acid metabolites, complex polysaccharides, and host lipids; such as sphingolipids and bile acids3-11. These metabolites profoundly affect host physiology and are being explored for their roles in both health and disease. Considering the diversity of the human microbiome, numbering over 40,000 operational taxonomic units12, a plethora of molecular diversity remains to be discovered. Here, we use unique mass spectrometry informatics approaches and data mapping onto a murine 3D-model13-15 to provide an untargeted assessment of the chemical diversity between germ-free (GF) and colonized mice (specific-pathogen free, SPF), and report the finding of novel bile acids produced by the microbiome in both mice and humans that have evaded characterization despite 170 years of research on bile acid chemistry16.

microbiology↗

MolNetEnhancer: enhanced molecular networks by integrating metabolome mining and annotation tools

Metabolomics has started to embrace computational approaches for chemical interpretation of large data sets. Yet, metabolite annotation remains a key challenge. Recently, molecular networking and MS2LDA emerged as molecular mining tools that find molecular families and substructures in mass spectrometry fragmentation data. Moreover, in silico annotation tools obtain and rank candidate molecules for fragmentation spectra. Ideally, all structural information obtained and inferred from these computational tools could be combined to increase the resulting chemical insight one can obtain from a data set. However, integration is currently hampered as each tool has its own output format and efficient matching of data across these tools is lacking. Here, we introduce MolNetEnhancer, a workflow that combines the outputs from molecular networking, MS2LDA, in silico annotation tools (such as Network Annotation Propagation or DEREPLICATOR) and the automated chemical classification through ClassyFire to provide a more comprehensive chemical overview of metabolomics data whilst at the same time illuminating structural details for each fragmentation spectrum. We present examples from four plant and bacterial case studies and show how MolNetEnhancer enables the chemical annotation, visualization, and discovery of the subtle substructural diversity within molecular families. We conclude that MolNetEnhancer is a useful tool that greatly assists the metabolomics researcher in deciphering the metabolome through combination of multiple independent in silico pipelines.

biochemistry↗

An omnidirectional visualization model of personalized gene regulatory networks

Gene regulatory networks (GRNs) have been widely used as a fundamental tool to reveal the genomic mechanisms that underlie the organisms response to environmental and developmental cues. Standard approaches infer GRNs as holistic graphs of gene co-expression, but such graphs cannot quantify how gene-gene interactions differentiate among organisms and how they alter structurally across spatiotemporal gradients. Here, we develop a generalized framework for inferring informative, dynamic, omnidirectional, and personalized GRNs (idopGRNs) from routine transcriptional experiments. This framework is constructed by a system of quasi-dynamic ordinary differential equations (qdODEs) derived from the combination of ecological and evolutionary theories. We reconstruct idopGRNs from a clinical genomic study and illustrate how network structure and organization affect surgical response to infrainguinal vein bypass grafting and the outcome of grafting. idopGNRs may shed light on genotype-phenotype relationships and provide valuable information for personalized medicine.

bioinformatics↗

Enrichment in conservative amino acid changes among fixed and standing missense variations in slow evolving proteins

Proteins were first used in the early 1960s to discover the molecular clock dating method and remain in common usage today in phylogenetic inferences based on neutral variations. To avoid substitution saturation, it is necessary to use slow evolving genes. However, it remains unclear whether fixed and standing missense changes in such genes may qualify as neutral. Here, based on the evolutionary rates as inferred from identity scores between orthologs in human and Macaca monkey, we found that the fraction of conservative amino acid mismatches between species was significantly higher in slow evolving proteins. We also examined the single nucleotide polymorphisms (SNPs) by using the 1000 genomes project data and found that missense SNPs in slow evolving proteins also had higher fraction of conservative changes, especially for common SNPs, consistent with more natural selection for SNPs, particularly rare ones, in fast evolving proteins. These results suggest that fixed and standing missense variations in slow evolving proteins are more likely to be neutral and hence better qualified for use in phylogenetic inferences.

evolutionary biology↗