Biology subjects

Wang, R.

Publications and source records attributed to Wang, R..

At least 487 records · Page 27Linked to original sources

bioRxiv2020

Cdc42 is required for lymphatic branching, maturation and valve formation during embryonic development

Cdc42, a Ras-related GTPase that regulates the actin cytoskeleton, was recently shown to play an indispensable role in vasculogenesis and endothelial cell (EC) survival. Here, we determined whether Cdc42 also contributes to lymphatic development by generated two different Cdc42 knockout mice lines by crossing Cdc42/flox mice with either vascular endothelial cadherin-Cre (Cdh5-Cre) mice or Prox1-CreERT2 mice. Our results demonstrated that depleting ECs of Cdc42 expression resulted in embryonic lethality with severe edema. Whole-mount immunofluorescence staining of both knockout embryos showed that the deletion of Cdc42 in ECs impaired lymphatic vessel branching and that the lymphatic lumen size significantly increased. Moreover, we found that the inactivation of Cdc42 compromised mesenteric collecting lymphatic vessel maturation and prevented valve formation. We go on to show that Cdc42 can be activated by vascular endothelial growth factor c (VEGFc) in cultured human dermal lymphatic ECs (HDLECs), and that knocking down Cdc42 expression in these cells using siRNA decreased VEGFc-induced focal adhesion kinase (FAK) phosphorylation. These findings, when taken together with the fact that inactivating FAK plus one allele of Cdc42 in ECs was sufficient to recapitulate the phenotypes of the Cdc42 EC knockout embryos, suggests that Cdc42 and FAK interact genetically during lymphatic development. In addition, Cdc42 and FAK regulated signal transduction is essential for blood and lymphatic vessel separation. Taken together, our data highlights the important role played by Cdc42 in the development of the lymphatic system.

developmental biology↗

bioRxiv2020

Src/FAK complex phosphorylates cardiac myosin binding protein c (cMyBP-C) in vitro and in vivo

Cardiac myosin binding protein C (cMyBP-C) is a phosphorylation-dependent force regulator and plays an important role in controlling myosin and actin dynamic interaction. Point-mutations of cMyBP-C that interfere with cMyBP-C threonine/serine phosphorylation resulted in hypertrophic cardiomyopathy and cardiac failure. However, it remains largely unknown how cMyBP-C tyrosine phosphorylation is regulated during cardiac hypertrophy and heart failure. Integrins are receptors of extracellular matrix and are the sensors of cardiac mechanical stretch. Focal adhesion kinase (FAK) plays an essential role in integrin-initiated signal transduction and regulates multiple cellular functions in various types of cells including cardiomyocytes. To identify the regulatory mechanism of cMyBP-C tyrosine phosphorylation during cardiac hypertrophy, we examined the effect of FAK on phosphorylation of cMyBP-C. Immunoprecipitation analysis showed that FAK and cMyBP-C are associated within the intact mouse heart. Results from our mutagenesis experiments demonstrated that the FAK kinase domain was required for FAK to associate with cMyBP-C. Our data also documented that the FAK Y397 site is required for FAK and cMyBP-C association. Importantly, overexpression dominant active Src Y527F with FAK significantly enhanced cMyBP-C phosphorylation. Interestingly, overexpression of cMyBP-C inhibited FAK phosphorylation. Taken together, cMyBP-C is one of effectors of Src/FAK complex in cardiomyocyte.

molecular biology↗

bioRxiv2020

Regulation of human development by ubiquitin chain editing of chromatin remodelers

Embryonic development occurs through commitment of pluripotent stem cells to differentiation programs that require highly coordinated changes in gene expression. Chromatin remodeling of gene regulatory elements is a critical component of how such changes are achieved. While many factors controlling chromatin dynamics are known, mechanisms of how different chromatin regulators are orchestrated during development are not well understood. Here, we describe LINKED (LINKage-specific-deubiquitylation-deficiency-induced Embryonic Defects) syndrome, a novel multiple congenital anomaly disorder caused by hypomorphic hemizygous missense variants in the deubiquitylase OTUD5/DUBA. Studying LINKED mutations in vitro, in mouse, and in models of neuroectodermal differentiation of human pluripotent stem cells, we uncover a novel regulatory circuit that coordinates chromatin remodeling pathways during early differentiation. We show that the K48-linkage-specific deubiquitylation activity of OTUD5 is essential for murine and human development and, if reduced, leads to aberrant cell-fate specification. OTUD5 controls differentiation through preventing the degradation of multiple chromatin regulators including ARID1A/B and HDAC2, mutation of which underlie developmental syndromes that exhibit phenotypic overlap with LINKED patients. Accordingly, loss of OTUD5 during early differentiation leads to less accessible chromatin at neural and neural crest enhancers and thus aberrant rewiring of gene expression networks. Our work identifies a novel mechanistic link between phenotypically related developmental disorders and an essential function for linkagespecific ubiquitin editing of substrate groups (i.e. chromatin remodeling complexes) during early cellfate decisions - a regulatory concept, we predict to be a general feature of embryonic development.

genetics↗

bioRxiv2020

Wnt signaling determines body axis polarity in regenerating Hydra tissue

How an animal establishes its body axis is a fundamental question in developmental biology. The freshwater cnidarian Hydra is an attractive model for studying axis formation because it is radially symmetric, with a single oral-aboral axis. It was recently proposed that the orientation of the new body axis in a regenerating Hydra is determined by the oral-aboral orientation of the actin-myosin contractile processes (myonemes) in the parent animals outer epithelial layer. However, because the myonemes are not known to possess polarity, it remained unclear how the oral-aboral polarity of the axis would be defined. As Wnt signaling is known to maintain axis polarity in Hydra and bilaterians, we hypothesized that it plays a role in axis specification in excised Hydra tissue pieces. We tested this hypothesis using pharmacological perturbations and novel grafting experiments to set Wnt-derived signals and myoneme orientation perpendicular to each other to determine which controls axis formation. Our results demonstrate that Wnt signaling is the dominant encoder of axis information, in line with its highly conserved role in anterior-posterior patterning.

developmental biology↗

bioRxiv2020

Dynamic metabolic reprogramming in dendritic cells: an early response to influenza infection that is essential for effector function

Infection with the influenza virus triggers an innate immune response aimed at initiating the adaptive response to halt viral replication and spread. However, the metabolic response fueling the molecular mechanisms underlying changes in innate immune cell homeostasis remain undefined. Thus, we compared the metabolic response of dendritic cells to that of those infected with active and inactive influenza A virus or treated with toll like receptor agonists. While influenza infects dendritic cells, it does not productively replicate in these cells, and therefore metabolic changes upon infection may represent an adaptive response on the part of the host cells. Using quantitative mass spectrometry along with pulse chase substrate utilization assays and metabolic flux measurements, we found global metabolic changes 17 hours post infection, including significant changes in carbon commitment via glycolysis and glutaminolysis, as well as ATP production via TCA cycle and oxidative phosphorylation. Influenza infection of dendritic cells led to a metabolic phenotype, distinct from that induced by TLR agonists, with significant resilience in terms of metabolic plasticity. We identified Myc as one transcription factor modulating this response. Restriction of either Myc activity or mitochondrial substrates resulted in significant changes in the innate immune functions of dendritic cells, including reduced motility and T cell activation. Transcriptome analysis of inflammatory dendritic cells isolated following influenza infection showed similar metabolic reprogramming occurs in vivo. Thus, early in the infection process dendritic cells respond with global metabolic restructuring that is present in lung DC 9 days following infection and impacts their effector function, suggesting that metabolic switching in dendritic cells plays a vital role in initiating the immune response to influenza infection. Author SummaryIn response to influenza infection we found that dendritic cells, cells that are critical in mounting an effective immune response, undergo a profound metabolic shift. They alter the concentration and location of hundreds of proteins, including c-MYC, mediating a shift to a highly glycolytic phenotype that is also flexible in terms of fueling respiration. Dendritic cells initiate the immune response to influenza and activate the adaptive response allowing viral clearance and manifesting immune memory for protection against subsequent infections. We found that limiting access to specific metabolic pathways or substrates diminished key immune functions. Previously we described an immediate, fixed, hypermetabolic state in infected respiratory epithelial cells. We now show the metabolic responses of epithelial and dendritic cells are distinct. Here, we also demonstrate that dendritic cells tailor their metabolic response to the pathogen or TLR stimulus. This metabolic reprogramming occurs rapidly in vitro and it is sustained in inflammatory dendritic cells in vivo for at least 9 days following influenza infection. Thus, drugs targeting metabolism are likely to have cell- and pathogen-specific activities in the context of infection. These studies open the possibility of modulating the immune response to viral infection via customizing metabolic therapy to enhance or diminish the function of specific cells.

immunology↗

bioRxiv2019

Dual role of auxin in regulating plant defense and bacterial virulence gene expression during Pseudomonas syringae PtoDC3000 pathogenesis.

Modification of host hormone biology is a common strategy used by plant pathogens to promote disease. For example, the bacterial pathogen Pseudomonas syringae strain PtoDC3000 produces the plant hormone auxin (Indole-3-acetic acid, or IAA) to promote PtoDC3000 growth in plant tissue. Previous studies suggest that auxin may promote PtoDC3000 pathogenesis through multiple mechanisms, including both suppression of salicylic acid (SA)-mediated host defenses and via an unknown mechanism that appears to be independent of SA. To test if host auxin signaling is important during pathogenesis, we took advantage of Arabidopsis thaliana lines impaired in either auxin signaling or perception. We found that disruption of auxin signaling in plants expressing an inducible dominant axr2-1 mutation resulted in decreased bacterial growth, demonstrating that host auxin signaling is required for normal susceptibility to PtoDC3000, and this phenotype was dependent on SA-mediated defenses. However, despite exhibiting decreased auxin perception, tir1 afb1 afb4 afb5 quadruple mutant plants lacking four of the six known auxin co-receptors supported increased levels of bacterial growth. This mutant also exhibited elevated IAA levels, suggesting that the increased IAA in these plants may promote PtoDC3000 growth independent of host auxin signaling, perhaps through a direct effect on the pathogen. In support of this, we found that IAA directly impacted the pathogen, by modulating expression of bacterial virulence genes, both in liquid culture and in planta. Thus, in addition to suppressing host defenses, IAA acts as a microbial signaling molecule that regulates bacterial virulence gene expression.

plant biology↗

bioRxiv2019

A CRISPR screen identifies UFMylation and TRAMP-like complexes required for hepatitis A virus infection

Hepatitis A virus (HAV) is a positive-sense RNA virus causing acute inflammation of the liver. Here, using a genome-scale CRISPR screen in a human hepatocyte cell line, we provide a comprehensive picture of the cellular factors, which are exploited by HAV during replication. We identified genes involved in sialic acid biosynthesis and members of the eukaryotic translation initiation factor complex, corroborating their putative roles in HAV infection. Additionally, we uncovered all components of the cellular machinery for UFMylation, a ubiquitin-like protein modification. We showed that HAV translation specifically depends on UFM1 conjugation of the ribosomal protein RPL26. Furthermore, we found that components related to the yeast Trf4/5- Air1/2-Mtr4 polyadenylation (TRAMP) complex, are required for viral translation, independent of controlling HAV poly(A) tails. While the identified HAV host factors were largely distinct compared to other picornaviruses, we highlighted a surprising co-dependency of HAV and hepatitis B virus (HBV) on the TRAMP-like complex. Finally, we demonstrated that pharmacological inhibition of the TRAMP-like complex decreased HAV replication in hepatocyte cells and human liver organoids, thus providing a strategy for host-directed therapy of HAV infection.

microbiology↗

bioRxiv2019

Dietary restriction transforms the protein sulfhydrome in a tissue-specific and cystathionine γ-lyase-dependent manner

Hydrogen sulfide (H2S) is a cytoprotective redox-active metabolite that signals through protein sulfhydration (R-SSnH). Despite the known importance of sulfhydration on relatively few identified proteins, tissue-specific sulfhydrome profiles and their associated functions are not well characterized, specifically under conditions known to modulate H2S production. We hypothesized that dietary restriction (DR), which increases lifespan and boosts endogenous H2S production, expands functional tissue-specific sulfhydromes. Here, we found that 50% DR enriched total sulfhydrated proteins in liver, kidney, muscle, and brain but decreased these in heart of adult male mice. DR promoted sulfhydration in numerous metabolic and aging-related pathways. Mice lacking the H2S producing enzyme cystathionine {gamma}-lyase (CGL) had decreased liver and kidney protein sulfhydration and failed to functionally augment their sulfhydrome in response to DR. Overall, we defined tissue- and CGL-dependent sulfhydromes and how diet transforms their makeup, underscoring the breadth for DR and H2S to impact biological processes and organismal health. One Sentence SummaryDietary restriction altered the tissue-specific enrichment of sulfhydrated proteins and their downstream signaling pathways in liver, kidney, skeletal muscle, brain, heart, and plasma that was partly dependent on the hydrogen sulfide producing enzyme cystathionine {gamma}-lyase.

physiology↗

bioRxiv2019

Dorsal Premotor Cortex Involved in Hand Gesture Preparation in Macaques

Reaching to grasp movement is thought to rely upon two independent brain pathways. The dorsomedial one is involved in reaching while the dorsolateral one is dealing with grasping. However, some recent evidences suggested that the dorsomedial pathway might participate in grasp movement. Therefore, it is important to investigate whether PMd is involved in grasp planning, and if participating, what kind of role PMd played in grasp planning. In this study, two macaques monkeys were trained to grasp same object by instructing or freely choosing one of two grips, power grip or hook grip. A 96-channel microelectrode array was implanted to collect the population activity of PMd in each subject. Both single unit activity and population activity were analyzed. We found that nearly 21.0% and 26.8% units in PMd of two monkeys displayed grip selectivity during gesture planning in both instructing or freely choosing conditions. These units exhibit selectivity for different gestures when facing the identical visual stimuli (freely choosing condition). At the same time, similar activity patterns are displayed for the same gesture when faced with different selection strategies (freely choosing condition vs. instructing condition). These results show that some neurons of PMd are mainly involved in the hand shape preparation and have no obvious relationship with external visual stimuli and selection strategies.

animal behavior and cognition↗

bioRxiv2019

DNA clamp function of the mono-ubiquitinated Fanconi Anemia FANCI-FANCD2 complex

The FANCI-FANCD2 (ID) complex, mutated in the Fanconi Anemia (FA) cancer predisposition syndrome, is required for the repair of replication forks stalled at DNA interstrand crosslinks (ICL) and related lesions1. The FA pathway is activated when two replication forks converge onto an ICL2, triggering the mono-ubiquitination of the ID complex. ID mono-ubiquitination is essential for ICL repair by excision, translesion synthesis and homologous recombination, but its function was hitherto unknown1,3. Here, the 3.48 [A] cryo-EM structure of mono-ubiquitinated ID (IDUb) bound to DNA reveals that it forms a closed ring that encircles the DNA. Compared to the cryo-EM structure of the non-ubiquitinated ID complex bound to ICL DNA, described here as well, mono-ubiquitination triggers a complete re-arrangement of the open, trough-like ID structure through the ubiquitin of one protomer binding to the other protomer in a reciprocal fashion. The structures, in conjunction with biochemical data, indicate the mono-ubiquitinated ID complex looses its preference for ICL and related branched DNA structures, becoming a sliding DNA clamp that can coordinate the subsequent repair reactions. Our findings also reveal how mono-ubiquitination in general can induce an alternate structure with a new function.

molecular biology↗

bioRxiv2019

Structure of the Fanconi Anemia Core-UBE2T complex poised to ubiquitinate bound FANCI-FANCD2

The Fanconi Anemia (FA) pathway is essential for the repair of DNA interstrand crosslinks (ICLs). The pathway is activated when a replication fork stalls because of an ICL or other replication stress. A central event in pathway activation is the mono-ubiquitination of the FANCI-FANCD2 (ID) complex by the FA Core complex, a ubiquitin ligase of nine subunits. Here we describe the cryo-EM structures of the 1.1 MDa FA Core at 3.1 angstroms, except for the FANCA subunit at 3.4, and of the complex containing Core, ID and the UBE2T ubiquitin conjugating enzyme at 4.2 angstroms. The Core has unusual stoichiometry with two copies of FANCB, FAAP100, FANCA, FAAP20, FANCG, FANCL, but only a single copy of FANCC, FANCE and FANCF. This is due to homodimers of FANCA and FANCB having incompatible 2-fold symmetry, resulting in an overall asymmetric assembly of the other subunits. The asymmetry is crucial, as it prevents the binding of a second FANC-C-E-F sub-complex that inhibits UBE2T recruitment by FANCL, and instead creates an ID binding site. The single active FANCL-UBE2T binds next to the FANCD2 ubiquitination site, prying open the FANCI-FANCD2 interface within which the ubiquitination sites are buried. These structures and biochemical data indicate a single active site ubiquitinates FANCD2 and FANCI sequentially, shedding light on a central event in the FA pathway.

molecular biology↗

bioRxiv2019

Development of Dynamic Functional Architecture during Early Infancy

Understanding the moment-to-moment dynamics of functional connectivity (FC) in the human brain during early development is crucial for uncovering neuro-mechanisms of the emerging complex cognitive functions and behaviors. Instead of calculating FC in a static perspective, we leveraged a longitudinal resting-state functional magnetic resonances imaging dataset from fifty-one typically developing infants and, for the first time, thoroughly investigated how the temporal variability of the FC architecture develops at the global (entire brain), meso- (functional system) and local (brain region) levels in the first two years of age. Our results revealed that, in such a pivotal stage, 1) the whole-brain FC dynamics is linearly increased; 2) the high-order functional systems display increased FC dynamics for both within- and between-network connections, while the primary systems show the opposite trajectories; 3) many frontal regions have increasing FC dynamics despite large heterogeneity in developmental trajectories and velocities. All these findings indicate that the brain is gradually reconfigured towards a more flexible, dynamic, and adaptive system with globally increasing but locally heterogeneous trajectories in the first two postnatal years, explaining why infants have emerging and rapidly developing high-order cognitive functions and complex behaviors.

neuroscience↗

bioRxiv2019

Separable regulation of POW1 in TAF2-mediated grain development and BR-mediated leaf angle formation in rice

Leaf angle is one of the key factors determining rice plant architecture. However, improvement of the leaf angle appears to be unsuccessful in practical breeding because of the simultaneous occurrence of unfavorable traits such as grain size reduction. In this study, we identified the pow1 (put on weight 1) mutant with enlarged grain size and leaf angle, typical brassinosteroid (BR)-related phenotypes caused by excessive cell proliferation and cell expansion. We show that POW1 encodes a novel protein functioning in grain size regulation by repressing the transcription activity of the interacting protein TAF2, a highly conserved member of the transcription initiation complex TFIID. Loss of function of POW1 increases the phosphorylation of OsBZR1 and decreases the inhibitory effect of OsBZR1 on the transcription of BR biosynthesis genes OsDWARF4 (D4) and D11, thus participates in BR-mediated leaf angle regulation. The separable functions of POW1 in grain size and leaf angle control provide a promising strategy to design high-yielding varieties in which both traits would be favorably developed, i.e., compact plant architecture and increased grain size, thus would promote the high-yield breeding a step forward in rice.

developmental biology↗

bioRxiv2019

Network-based metrics of community resilience and dynamics in lake ecosystems

Some ecosystems undergo abrupt transitions to a new regime after passing a tipping point in an exogenous stressor, for example lakes shifting from a clear to turbid eutrophic state in response to nutrient-enrichment. Metrics-based resilience indicators have been developed as early warning signals of these shifts but have not always proved reliable indicators. Alternative approaches focus on changes in the composition and structure of an ecosystem, which can require long-term food-web observations that are typically beyond the scope of monitoring. Here we prototype a network-based algorithm for estimating ecosystem resilience, which reconstructs past ecological networks solely from palaeoecological abundance data. Resilience is estimated using local stability analysis, and eco-net energy: a neural network-based proxy for ecological memory. We test the algorithm on modelled (PCLake+) and empirical (lake Erhai) data. The metrics identify increasing diatom community instability during eutrophication in both cases, with eco-net energy revealing complex eco-memory dynamics. The concept of ecological memory opens a new dimension for understanding ecosystem resilience and regime shifts, with eco-memory potentially increasing ecosystem resilience by allowing past memorised eco-network states to be recovered after disruptions.

ecology↗

bioRxiv2019

Principles of RNA processing from analysis of enhanced CLIP maps for 150 RNA binding proteins.

A critical step in uncovering rules of RNA processing is to study the in vivo regulatory networks of RNA binding proteins (RBPs). Crosslinking and immunoprecipitation (CLIP) methods enabled mapping RBP targets transcriptome-wide, but methodological differences present challenges to large-scale integrated analysis across datasets. The development of enhanced CLIP (eCLIP) enabled the large-scale mapping of targets for 150 RBPs in K562 and HepG2, creating a unique resource of RBP interactomes profiled with a standardized methodology in the same cell types. Here we describe our analysis of 223 enhanced (eCLIP) datasets characterizing 150 RBPs in K562 and HepG2 cell lines, revealing a range of binding modalities, including highly resolved positioning around splicing signals and mRNA untranslated regions that associate with distinct RBP functions. Quantification of enrichment for repetitive and abundant multi-copy elements reveals 70% of RBPs have enrichment for non-mRNA element classes, enables identification of novel ribosomal RNA processing factors and sites and suggests that association with retrotransposable elements reflects multiple RBP mechanisms of action. Analysis of spliceosomal RBPs indicates that eCLIP resolves AQR association after intronic lariat formation (enabling identification of branch points with single-nucleotide resolution) and provides genome-wide validation for a branch point-based scanning model for 3 splice site recognition. Further, we show that eCLIP peak co-occurrences across RBPs enables the discovery of novel co-interacting RBPs. Finally, we present a protocol for visualization of RBP:RNA complexes in the eCLIP workflow using biotin and standard chemiluminescent visualization reagents, enabling simplified confirmation of ribonucleoprotein enrichment without radioactivity. This work illustrates the value of integrated analysis across eCLIP profiling of RBPs with widely distinct functions to reveal novel RNA biology. Further, our quantification of both mRNA and other element association will enable further research to identify novel roles of RBPs in regulating RNA processing.

genomics↗

bioRxiv2019

Inference of Single-Cell Phylogenies from Lineage Tracing Data

The pairing of CRISPR/Cas9-based gene editing with massively parallel single-cell readouts now enables large-scale lineage tracing. However, the rapid growth in complexity of data from these assays has outpaced our ability to accurately infer phylogenetic relationships. To address this, we provide three resources. First, we introduce Cassiopeia - a suite of scalable and theoretically grounded maximum parsimony approaches for tree reconstruction. Second, we provide a simulation framework for evaluating algorithms and exploring lineage tracer design principles. Finally, we generate the most complex experimental lineage tracing dataset to date - consisting of 34,557 human cells continuously traced over 15 generations, 71% of which are uniquely marked - and use it for benchmarking phylogenetic inference approaches. We show that Cassiopeia outperforms traditional methods by several metrics and under a wide variety of parameter regimes, and provide insight into the principles for the design of improved Cas9-enabled recorders. Together these should broadly enable large-scale mammalian lineage tracing efforts. Cassiopeia and its benchmarking resources are publicly available at www.github.com/YosefLab/Cassiopeia.

bioinformatics↗

bioRxiv2019

FMRP Control of Ribosome Translocation Promotes Chromatin Modifications and Alternative Splicing of Neuronal Genes Linked to Autism

Silencing of FMR1 and loss of its gene product FMRP results in Fragile X Syndrome. FMRP binds brain mRNAs and inhibits polypeptide elongation. Using ribosome profiling of the hippocampus, we find that ribosome footprint levels in Fmr1-deficient tissue mostly reflect changes in RNA abundance. Profiling over a time course of ribosome runoff in wildtype tissue reveals a wide range of ribosome translocation rates; on many mRNAs, the ribosomes are stalled. Sucrose gradient ultracentrifugation of hippocampal slices after ribosome runoff reveals that FMRP co-sediments with stalled ribosomes; and its loss results in decline of ribosome stalling on specific mRNAs. One such mRNA encodes SETD2, a lysine methyltransferase that catalyzes H3K36me3. ChIP-Seq demonstrates that loss of FMRP alters the deployment of this epigenetic mark on chromatin. H3K36me3 is associated with alternative pre-RNA processing, which we find occurs in an FMRP-dependent manner on transcripts linked to neural function and autism spectrum disorders. Highlights- Loss of FMRP results in decline of ribosome stalling on specific mRNAs (eg., SETD2) - Increased SETD2 protein levels alter H3K36me3 marks in FMRP deficient hippocampus - Genome-wide changes in mRNA alternative splicing occur in FMRP deficient hippocampus - H3K36me3 marks and alternative splicing changes occur on transcripts linked to autism

neuroscience↗

bioRxiv2019

Hsa_circ_0001947 suppresses acute myeloid leukemia progression by sponging hsa-miR-329-5p and regulating CREBRF expression

Acute myeloid leukemia (AML) is a heterogeneous group of diseases resulting from clonal transformation of hematopoietic precursors through the acquisition of chromosomal rearrangements and multiple gene mutations. Accumulating evidence has indicated that aberrantly expressed circular RNAs (circRNAs) are involved in cancer development and progression. However, their clinical values and biological roles in AML remain unclear. In this study, we identified the aberrantly down-regulated profile of hsa_circ_0001947 in AML through microarray analysis and validated it with quantitative reverse transcription polymerase chain reaction (qRT-PCR). Then, we explored the clinical significance, biological functions and regulatory mechanisms of hsa_circ_0001947 in AML patients. The results showed that lower hsa_circ_0001947 expression was positively correlated with higher leukemia cells in bone marrow or peripheral blood, indicating poor prognosis. Further, bioinformatics analysis demonstrated hsa_circ_0001947-hsa-miR-329-5p-CREBRF network. Down-regulation of hsa_circ_0001947 by siRNA promoted cell proliferation, inhibited apoptosis, reduced drug resistance of AML cells, and also decreased the expression of its targeted gene, CREBRF. The mimics of hsa-miR-329-5p reduced drug resistance and decreased the expression of CREBRF, while its inhibitor manifested anti-leukemia effects and increased CREBRF expression. In vivo studies revealed that silencing hsa_circ_0001947 promoted the tumor growth in BALB/c nude mice. Collectively, our findings suggest that hsa_circ_0001947 functions as a tumor inhibitor to suppress AML cell proliferation through hsa-miR-329-5p/CREBRF axis, which would be a novel target for AML therapy.

cancer biology↗