Biology subjects

Tang, W.

Publications and source records attributed to Tang, W..

At least 127 records · Page 7Linked to original sources

bioRxiv2021

Combined oncolytic adenovirus carrying MnSOD and mK5 genes both regulated by survivin promoter has synergistic inhibitory effect on gastric cancer

Gastric cancer (GC) is one of the major causes of cancer related mortality. The use of oncolytic virus for cancer gene-virotherapy is a new approach for the treatment of human cancers. In this study, a novel Survivin promoter driven recombinant oncolytic adenovirus carrying mK5 or MnSOD gene was constructed, which was modified after deletion of E1B gene. Human plasminogen Kringle 5 mutant (mK5) and manganese superoxide dismutase (MnSOD) are both potential tumor suppressor genes. To construct Ad-Surp-mK5 and Ad-Surp-MnSOD oncolytic adenovirus, we hypothesized that the combination of the two viruses would enhance the therapeutic efficacy of GC as compared to the virus alone. The results of the in vitro experiments revealed that the combination of adenovirus carrying mK5 and MnSOD gene exhibited stronger cytotoxicity to GC cell lines as compared to the virus alone, Additionally, the virus could selectively kill cancer cells and human somatic cells. Cell staining, flow cytometry and western blot analysis showed that the combination of two adenovirus containing therapeutic genes could promote the apoptosis of cancer cells. In vivo experiments further verified that Ad-Surp-mK5 in combination with Ad-Surp-MnSOD exhibited significant inhibitory effect on the growth of GC tumor xenograft as compared to the virus alone, and no significant difference was observed in the body weight of treatment and the normal mice. In conclusion, the combination of our two newly constructed recombinant oncolytic adenovirus containing mK5 or MnSOD therapeutic genes could significantly inhibit gastric cancer growth by inducing apoptosis, suggestive of its potential for GC therapy.

cancer biology↗

bioRxiv2021

Mechano-transduction via the pectin-FERONIA complex regulates ROP6 GTPase signaling in Arabidopsis

During growth and morphogenesis, plant cells respond to mechanical stresses resulting from spatiotemporal changes in the cell wall that bear high internal turgor pressure. Microtubule (MT) arrays are re-organized to align in the direction of maximal tensile stress to guide the synthesis of cellulose, reinforcing the local cell wall. However, how mechanical forces regulate MT re-organization remains largely unknown. Here, we demonstrate that mechanical signaling that is based on the CrRLK1L subfamily receptor kinase FERONIA (FER) regulates the reorganization of cortical MT in cotyledon epidermal pavement cells (PC) in Arabidopsis. Recessive mutations in FER compromised MT response to mechanical perturbations such as single cell ablation, compression and Isoxaben treatment in these pavement cells. These perturbations promoted the activation of ROP6 GTPase that acts directly downstream of FER. Furthermore, defects in the ROP6 signaling pathway negated the reorganization of cortical MTs induced by these stresses. Finally, reduction in highly demethylesterified pectin, which binds the extracellular malectin domain of FER and is required for FER-mediated ROP6 activation, also impacted mechanical induction of cortical MT reorganization. Taken together our results suggest that the FER-pectin complex senses and/or transduce mechanical forces to regulate MT organization through activating the ROP6 signaling pathway in Arabidopsis.

cell biology↗

bioRxiv2021

Intracellular Oxidative Stress Levels are Significantly Associated with the Green Autofluorescence Intensity of Buthionine Sulfoximine-Treated B16-F10 Cells

Since oxidative stress is a critical common pathological factor of numerous diseases, it is critical to find biomarkers for non-invasive evaluations of the levels of oxidative stress in the body. Our previous studies have indicated that epidermal green autofluorescence (AF) is a novel biomarker of this type: The oxidative stress inducer buthionine sulfoximine (BSO) can dose-dependently increase the epidermal green AF of mice, with BSO doses being significantly associated with the AF intensity. However, it is necessary to use skin cell cultures to investigate the mechanisms underlying the relationships between BSO and the green AF intensity. In our current study we found that BSO concentration-dependently increased the green AF intensity of B16-F10 cells a skin cell line, with BSO concentrations being significantly associated with the AF intensity. BSO also concentration-dependently increased the intracellular DCF signals an index of ROS levels. The green AF intensity of the cells was also significantly associated with the intracellular ROS levels. Moreover, we found that the green AF intensity was significantly associated with the cell death induced by BSO. Collectively, our study has provided first evidence indicating that the green AF intensity of skin cells is significantly associated with both intracellular ROS levels and cell death of the skin cells exposed to oxidative stress, which has indicated that green AF is a novel biomarker for both oxidative stress and cell death.

biophysics↗

bioRxiv2021

De novo purine nucleotide biosynthesis mediated by amidophosphoribosyl transferase is required for conidiation and essential for the successful host colonization of Magnaporthe oryzae

Amidophosphoribosyl transferase catalyzes the first step of the purine nucleotide biosynthesis by converting 5-phosphoribosyl-1-pyrophosphate into 5-phosphoribosyl-1-amine. In this study, we identified and characterized the functions of MoAde4, an ortholog of yeast Ade4 in the rice blast fungus. MoAde4 is a 537-amino acid protein containing the GATase_6 and pribosyltran domains. Quantitative real-time PCR analysis showed MoADE4 transcripts were highly expressed during conidiation, early-infection, and late-infection stages of the fungus. Disruption of MoADE4 gene resulted in {Delta}Moade4 mutant exhibiting adenine, adenosine, and hypoxanthine auxotrophy on MM. Conidia quantification assays showed {Delta}Moade4 mutant was significantly reduced in sporulation. The conidia of {Delta}Moade4 mutant could still form appressoria but mostly failed to penetrate the rice cuticle. Pathogenicity test showed {Delta}Moade4 was completely nonpathogenic on rice and barley leaves which was attributed by failure of its infectious hyphae to colonize the host cells. The {Delta}Moade4 was defective in induction of strong host immunity and had its purine transporter genes repressed during in planta infection. Addition of exogenous adenine partially rescued conidiation and pathogenicity defects of the {Delta}Moade4 mutant on the barley and rice leaves. Localization assays showed that MoAde4 is located in the cytoplasm. Taken together, our results demonstrate that purine biosynthesis orchestrated by MoAde4 is required for fungal development, conidiation, more importantly, we found it to be essential for fungal pathogenicity not because of the appressorial formation, but appressorium penetration and host colonization during the plant infection of M. oryzae. Thus this findings suggests that purine biosynthesis could act as an important target for combating recalcitrant plant fungal pathogens.

molecular biology↗

bioRxiv2020

MoCpa1-mediated arginine biosynthesis is crucial for fungal growth, conidiation, and plant infection of Magnaporthe oryzae

Arginine is an important amino acid involved in processes such as cell signal transduction, protein synthesis, and sexual reproduction. To understand the biological roles of arginine biosynthesis in pathogenic fungi, we used Cpa1, the carbamoyl phosphate synthase arginine-specific small chain subunit in Saccharomyces cerevisiae as a query to identify its ortholog in Magnaporthe oryzae genome database and named it MoCpa1. MoCpa1 is a 471-amino acid protein containing the CPSase_sm_chain domain and the GATase domain. MoCpa1 transcripts were highly expressed at the conidiation, early-infection, and late-infection stages of the fungus. Targeted deletion of MoCPA1 gene resulted in the {Delta}Mocpa1 mutant exhibiting arginine auxotrophy on MM, confirming its role in de novo arginine biosynthesis. The {Delta}Mocpa1 mutant presented significantly decreased sporulation with some of its conidia being defective in morphology. Furthermore, the {Delta}Mocpa1 mutant was nonpathogenic on rice and barley leaves, which was a result of defects in appressorium-mediated penetration and restricted invasive hyphal growth within host cells. Addition of exogenous arginine partially rescued conidiation and pathogenicity defects on the barley and rice leaves, while introduction of MoCPA1 gene in {Delta}Mocpa1 mutant fully complemented the lost phenotype. Further confocal microscopy examination revealed that MoCpa1 is localized in the mitochondria. In summary, our results demonstrate that MoCpa1-mediated arginine biosynthesis is crucial for fungal development, conidiation, appressorium formation and infection-related morphogenesis in M. oryzae, thus serving as an attractive target for mitigating obstinate fungal plant pathogens.

molecular biology↗

bioRxiv2020

SARS-CoV-2 infecting the inner ear results in potential hearing damage at the early stage or prognosis of COVID-19 in rodents

ObjectivesIn order to find out the association between the sensorineural hearing loss and COVID-19, we detected the expression ACE2 and TMPRSS2 in the mouse the hamster. DesignUsing the public data from NCBI and GISAID, we assessed the expression of ACE2 and TMPRSS2 at the transcriptomic, DNA, and protein levels of ACE2 in the brain, inner ear, and muscle from the golden Syrian hamster (Mesocricetus auratus) and mouse (Mus musculus). ResultsWe identified ACE2 and TMPRSS2 expressed at different level in the inner ear and brain at DNA and transcriptomic levels of both mouse and the hamster. The protein expression shows a similar pattern of the brain and inner ear, while the expression of ACE2 from the inner ear was relatively higher than it from the muscle. ConclusionSARS-CoV-2 could infect the hearing system potentially and SSNHL could be a characteristic to detect asymptomatic patients of COVID-19.

bioinformatics↗

bioRxiv2020

Cardiomyopathy Mutations Impact the Power Stroke of Human Cardiac Myosin

Cardiac muscle contraction is driven by the molecular motor myosin that uses the energy from ATP hydrolysis to generate a power stroke when interacting with actin filaments, while it is unclear how this mechanism is impaired by mutations in myosin that can lead to heart failure. We have applied a Forster resonance energy transfer (FRET) strategy to investigate structural changes in the lever arm domain of human {beta}-cardiac myosin subfragment 1 (M2{beta}-S1). We exchanged the human ventricular regulatory light chain labeled at a single cysteine (V105C) with Alexa 488 onto M2{beta}-S1, which served as a donor for Cy3ATP bound to the active site. We monitored the FRET signal during the actin-activated product release steps using transient kinetic stopped-flow measurements. We proposed that the fast phase measured with our FRET probes represents the structural change associated with rotation of the lever arm during the power stroke in M2{beta}-S1. Our results demonstrated human cardiac muscle myosin has a slower power stroke compared with fast skeletal muscle myosin and myosin V. Measurements at different temperatures comparing the rate constants of the power stroke and phosphate release revealed that the power stroke occurs before phosphate release, and the two steps are tightly coupled. We speculate that the slower power stroke rate constant in cardiac myosin may correlate with the slower force development and/or unique thin filament activation properties in cardiac muscle. Additionally, we demonstrated that HCM (R723G) and DCM (F764L) associated mutations both reduced actin-activation of the power stroke in M2{beta}-S1. We also demonstrate that both mutations decrease ensemble force development in the loaded in vitro motility assay. Thus, examining the structural kinetics of the power stroke in M2{beta}-S1 has revealed critical mutation-associated defects in the myosin ATPase pathway, suggesting these measurements will be extremely important for establishing structure-based mechanisms of contractile dysfunction. SignificanceMutations in human beta-cardiac myosin are known to cause various forms of heart disease, while it is unclear how the mutations lead to contractile dysfunction and pathogenic remodeling of the heart. In this study, we investigated two mutations with opposing phenotypes and examined their impact on ATPase cycle kinetics, structural changes associated with the myosin power stroke, and ability to slide actin filaments in the presence of load. We found that both mutations impair the myosin power stroke and other key kinetic steps as well as the ability to produce ensemble force. Thus, our results provide a structural basis for how mutations disrupt molecular level contractile dysfunction.

biophysics↗

bioRxiv2020

Natural SARS-CoV-2 infections, including virus isolation, among serially tested cats and dogs in households with confirmed human COVID-19 cases in Texas, USA

The natural infections and epidemiological roles of household pets in SARS-CoV-2 transmission are not understood. We conducted a longitudinal study of dogs and cats living with at least one SARS-CoV-2 infected human in Texas and found 47.1% of 17 cats and 15.3% of 59 dogs from 25.6% of 39 households were positive for SARS-CoV-2 via RT-PCR and genome sequencing or neutralizing antibodies. Virus was isolated from one cat. The majority (82.4%) of infected pets were asymptomatic. Re-sampling of one infected cat showed persistence of viral RNA at least 32 d-post human diagnosis (25 d-post initial test). Across 15 antibody-positive animals, titers increased (33.3%), decreased (33.3%) or were stable (33.3%) over time. A One Health approach is informative for prevention and control of SARS-CoV-2 transmission.

zoology↗

bioRxiv2020

Discovery of rhodomyrtone as a broad-spectrum antiviral inhibitor with anti-SARS-CoV-2 activity

The outbreak of new viruses, such as serve acute respiratory syndrome coronavirus 2 (SARS-CoV-2), as well as the emerging of drug-resistance viruses highlight the urgent need for the development of broad-spectrum antiviral drugs. Herein, we report the discovery of a plant-derived small molecule, 6,8-dihydroxy-9-isobutyl-2,2,4,4-tetramethyl-7-(3-methylbutanoyl)-4,9-dihydro-1H-xanthene-1,3(2H)-dione (rhodomyrtone, RDT), which exhibited potent broad-spectrum antiviral activities against several RNA and DNA viruses, including SARS-CoV-2, respiratory syncytial virus (RSV), herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2), varicella-zoster virus (VZV), human cytomegalovirus (HCMV), and Kaposis sarcoma-associated herpesvirus (KSHV). RDT can significantly suppress viral gene expression and show the low possibility to elicit drug-resistant variants. Mechanistic study implied that RDT inhibited viral infection by disturbing the cellular factors that essential for viral gene expression. Our results suggested that RDT might be a promising lead compound for the development of broad-spectrum antiviral drugs.

pharmacology and toxicology↗

bioRxiv2020

Membrane Ca2+ permeability and IP3R2 dependent Ca2+-induced Ca2+ release are essential for astrocytic intracellular Ca2+ elevation upon neuronal stimulation at the mouse hippocampal CA3 - CA1 excitatory synapses

Astrocytes are intricately involved in the activity of neural circuits, however, their basic physiology of interacting with neurons remains controversial. Using dual-indicator two-photon imaging of neurons and astrocytes during stimulations of hippocampal CA3 - CA1 Schaffer collateral (Scc) excitatory synapses, we report that under physiological conditions, the increased glutamate released from the higher frequency stimulation of neurons can accelerate local astrocytic Ca2+ levels. As consequences of extracellular glutamate clearance and maintaining of astrocytic intracellular Na+ homeostasis, the increase of astrocytic membrane Ca2+ permeability via Na+/Ca2+ exchanger (NCX) reverse mode is the primary reason of eliciting astrocytic intracellular Ca2+ elevation upon neuronal stimulation. This Ca2+-induced Ca2+ release is dependent on inositol triphosphate receptor type 2 (IP3R2). In addition, ATP released from Scc excitatory synapses can contribute to this molecular mechanism of Ca2+-induced Ca2+ release in astrocytes.

neuroscience↗

bioRxiv2020

Multiple time-scales of decision making in the hippocampus and prefrontal cortex

The prefrontal cortex and hippocampus are crucial for memory-guided decision-making. Neural activity in the hippocampus exhibits place-cell sequences at multiple timescales, including slow behavioral sequences ([~]seconds) and fast theta sequences ([~]100-200 ms) within theta oscillation cycles. How prefrontal ensembles interact with hippocampal sequences to support decision-making is unclear. Here, we examined simultaneous hippocampal and prefrontal ensemble activity during learning of a spatial working-memory decision task. We found clear theta sequences in prefrontal cortex, nested within its behavioral sequences. In both regions, behavioral sequences maintained representations of current goals during navigation. In contrast, hippocampal theta sequences encoded alternatives for deliberation, and were coordinated with prefrontal theta sequences that predicted upcoming choices. During error trials, these representations were preserved to guide ongoing behavior, whereas replay sequences during inter-trial periods were impaired prior to navigation. These results establish cooperative interaction between hippocampal and prefrontal sequences at multiple timescales for memory-guided decision making.

neuroscience↗

bioRxiv2020

MCM complexes are barriers that restrict cohesin-mediated loop extrusion

Eukaryotic genomes are compacted into loops and topologically associating domains (TADs), which contribute to transcription, recombination and genomic stability. Cohesin extrudes DNA into loops that are thought to lengthen until CTCF boundaries are encountered. Little is known about whether loop extrusion is impeded by DNA-bound macromolecular machines. We demonstrate that the replicative helicase MCM is a barrier that restricts loop extrusion in G1 phase. Single-nucleus Hi-C of one-cell embryos revealed that MCM loading reduces CTCF-anchored loops and decreases TAD boundary insulation, suggesting loop extrusion is impeded before reaching CTCF. Single-molecule imaging shows that MCMs are physical barriers that frequently constrain cohesin translocation in vitro. Simulations are consistent with MCMs as abundant, random barriers. We conclude that distinct loop extrusion barriers contribute to shaping 3D genomes. One Sentence SummaryMCM complexes are obstacles that impede the formation of CTCF-anchored loops.

cell biology↗

bioRxiv2020

lncRNA-RMST functioned as a SOX2 transcription co-regulator to regulate miR-1251 in the progression of Hirschsprung's disease

Hirschsprungs disease (HSCR) is a congenital disorder characterized by the absence of enteric neural crest cells (ENCCs). Non-coding RNAs including long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have been authenticated as important regulators of biological functions. We conducted a microarray analysis and found lncRNA Rhabdomyosarcoma 2-associated transcript (RMST) was down-regulated in the stenotic segment of HSCR patients. MiR-1251 is transcribed from the intron region of RMST and was also low-expressed. When the expression of RMST or miR-1251 was reduced, the cell proliferation and migration were attenuated. However, RMST didnt affect the expression of miR-1251 directly found in this study. Through bioinformatic analysis, transcription factor SOX2 was predicted to bind to the promoter region of miR-1251 which was confirmed by CHIP assay. Herein, we demonstrated that RMST exerted as a co-regulator of SOX2 to regulate the expression of miR-1251. Furtherly, AHNAK was proved to be the target gene of miR-1251 in this study. Taken together, we revealed the role of RMST/SOX2/miR-1251/AHNAK pathway in the occurrence of Hirschsprungs disease and provided a potential therapeutic target for this disease. SUMMARY STATEMENTHirschsprung disease (HSCR) is characterized by a deficit in enteric neurons, however, the underlying mechanism remains unclear. This study revealed the role of lnc-RMST during the occurrence of HSCR.

cell biology↗

bioRxiv2020

Higher-order sensorimotor circuit of the brain' global network supports human consciousness

The neural correlates of consciousness, defined as the minimum neuronal mechanisms sufficient for any conscious percept, are usually subject to different interpretations depending on whether one uses measures of local or global brain activities. We argue that the local regions may support consciousness by serving as hubs within the brains global network. We adopt a unique functional magnetic resonance imaging resting state dataset that encompasses various conscious states, including non-rapid eye movement (NREM)-sleep, rapid eye movement (REM)-sleep, anesthesia, and brain injury patients. Using a graph-theoretical measure for detecting local hubs within the brains global network, we identify various higher-order sensory and motor regions as hubs with significantly reduced degree centrality during unconsciousness. Additionally, these regions form a sensorimotor circuit which correlates with levels of consciousness. Our findings suggest that integration of higher-order sensorimotor function may be a key mechanism of consciousness. This opens novel perspectives for therapeutic modulation of unconsciousness.

neuroscience↗

bioRxiv2020

Oxidized Lipids and CD36-Mediated Lipid Peroxidation in CD8 T Cells Suppress Anti-Tumor Immune Responses

T cell metabolic fitness plays a pivotal role in anti-tumor immunity and metabolic deregulation causes T cell dysfunction (i.e., exhaustion) in cancer. We identify that the scavenger receptor CD36 limits anti-tumor CD8+ T cell effector functions through lipid peroxidation. In murine tumors, oxidized phospholipids (OxPLs) were highly abundant and CD8+ TILs increased uptake and accumulation of lipids and lipid peroxidation. Functionally exhausted CD8+ TILs substantially increased CD36 expression and CD36-deficient CD8+ TILs had more robust anti-tumor activity and cytokine production than wild-type cells. We further show that CD36 promotes uptake of oxidized low-density lipoproteins (OxLDL) and induces lipid peroxidation in CD8+ TILs, and OxLDL inhibits CD8+ T cell functions in a CD36-dependent manner. Moreover, glutathione peroxidase 4 (GPX4) over-expression lowers lipid peroxidation and restores functionalities in CD8+ TILs. These results define a key role for an oxidized lipid-CD36 axis in promoting intratumoral CD8+ T cell dysfunction.

immunology↗

bioRxiv2020

Inflammation mediates lung cancer-induced increase in the epidermal green autofluorescence of mice

Skins autofluorescence (AF) holds great promise for non-invasive diagnosis of diseases. Our previous study has indicated that keratin-based skins AF holds great promise to become a novel biomarker for diagnosis of multiple major diseases, including lung cancer, acute ischemic stroke, Parkinsons diseases, stable coronary artery disease and myocardial infarction. It is critical to investigate the mechanisms underlying the increased skins AF of the patients. Our previous study has shown that development of lung cancer can induce increased skins green AF of mice, while the mechanisms underlying the increased AF have remained unclear. We hypothesized that the inflammation in the mice with lung cancer is causative to the increased AF. Our study found that the anti-inflammation drug indomethacin virtually abolished the lung cancer-induced increase in the skins green AF. We further found that the AF was originated from the epidermis of the mice. Our findings have provided critical information for understanding the mechanisms underlying the lung cancer-induced increase in the epidermal green AF, indicating that at least for lung cancer, the disease-induced increase in the skins AF mainly results from increased inflammation in the body.

biophysics↗

bioRxiv2020

Specification and epigenetic resetting of the pig germline exhibit conservation with the human lineage

Investigations on the human germline and programming are challenging due to limited access to embryonic material. However, the pig as a model may provide insight on transcriptional network and epigenetic reprogramming applicable to both species. Here we show that during the pre- and early migratory stages pig primordial germ cells (PGCs) initiate large-scale epigenetic reprogramming, including DNA demethylation involving TET-mediated hydroxylation and potentially base excision repair (BER). There is also macroH2A1 depletion and increased H3K27me3, as well as X chromosome reactivation (XCR) in females. Concomitantly, there is dampening of glycolytic metabolism genes and re-expression of some pluripotency genes like those in preimplantation embryos. We identified evolutionarily young transposable elements and gene coding regions resistant to DNA demethylation in acutely hypomethylated gonadal PGCs, with potential for transgenerational epigenetic inheritance. Detailed insights into the pig germline will likely contribute significantly to advances in human germline biology, including in vitro gametogenesis.

developmental biology↗

bioRxiv2020

Binding Ability Prediction between Spike Protein and Human ACE2 Reveals the Adaptive Strategy of SARS-CoV-2 in Humans

SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is a novel coronavirus causing an outbreak of COVID-19 globally in the past six months. A relatively higher divergence on the spike protein of SASR-CoV-2 enables it to transmit across species efficiently. We particularly believe that the adaptive mutations of the receptor-binding domain (RBD) of spike protein in SARS-CoV-2 might be essential to its high transmissibility among humans. Thus here we collected 2,142 high-quality genome sequences of SARS-CoV-2 from 160 regions in over 50 countries and reconstructed their phylogeny, and also analyzed the interaction between the polymorphisms of spike protein and human ACE2 (hACE2). Phylogenetic analysis of SARS-CoV-2 and coronavirus in other hosts show SARS-CoV-2 is highly possible originated from Bat-CoV (RaTG13) found in horseshoe bat and a recombination event may occur on the spike protein of Pangolin-CoV to imbue it the ability to infect humans. Moreover, compared to the S gene of SARS-CoV-2, it is more conserved in the direct-binding sites of RBD and we noticed that spike protein of SARS-CoV-2 may under a consensus evolution to adapt to human hosts better. 3,860 amino acid mutations in spike protein RBD (T333-C525) of SARS-CoV-2 were simulated and their stability and affinity binding to hACE2 (S19-D615) were calculated. Our analysis indicates SARS-CoV-2 could infect humans from different populations with no preference, and a higher divergence in the spike protein of SARS-CoV-2 at the early stage of this pandemic may be a good indicator that could show the pathway of SARS-CoV-2 transmitting from the natural reservoir to human beings.

microbiology↗