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Tong, Y.

Publications and source records attributed to Tong, Y..

At least 73 records · Page 4Linked to original sources

Identification and characterization of a beta-1,4 Galactosidase from Elizabethkingia meningoseptica and its application on living cell surface

The biological function of terminal galactose on glycoprotein is an open field of research. Although progress had being made on enzymes that can remove the terminal galactose on glycoproteins, there is a lack of report on galactosidases that can work directly on living cells. In this study, a unique beta 1,4 galactosidase was isolated from Elizabethkingia meningoseptica (Em). It exhibited favorable stability at various temperatures (4-37) and pH (5-8) levels and can remove {beta}-1, 4 linked galactoses directly from glycoproteins. Using Alanine scanning, we found that two acidic residues (Glu-468, and Glu-531) in the predicted active pocket are critical for galactosidase activity. In addition, we also demonstrated that it could cleave galactose residues present on living cell surface. As the enzyme has a potential application for living cell glycan editing, we named it glycan editing galactosidase I or geGalaseI. In summary, our findings lay the groundwork for prospective investigations by presenting a prompt and gentle approach for the removal of galactose moieties from cell surface.

biochemistry↗

Cell autonomous role of leucine-rich repeat kinase in protection of dopaminergic neuron survival

Mutations in leucine-rich repeat kinase 2 (LRRK2) are the most common genetic cause of Parkinsons disease (PD), which is the leading neurodegenerative movement disorder characterized by the progressive loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc). However, whether LRRK2 mutations cause PD and degeneration of DA neurons via a toxic gain-of-function or a loss-of-function mechanism is unresolved and has pivotal implications for LRRK2-based PD therapies. In this study, we investigate whether LRRK2 and its functional homologue LRRK1 play an essential, intrinsic role in DA neuron survival through the development of DA neuron-specific LRRK conditional double knockout (cDKO) mice. We first generated and characterized floxed LRRK1 and LRRK2 mice and then confirmed that germline deletions of the floxed LRRK1 and LRRK2 alleles result in null mutations, as evidenced by the absence of LRRK1 and LRRK2 mRNA and protein in the respective homozygous deleted mutant mice. We further examined the specificity of Cre-mediated recombination driven by the dopamine transporter-Cre (DAT-Cre) knockin (KI) allele using a GFP reporter line and confirmed that DAT-Cre-mediated recombination is restricted to DA neurons in the SNpc. Crossing these validated floxed LRRK1 and LRRK2 mice with DAT-Cre KI mice, we then generated DA neuron-restricted LRRK cDKO mice and further showed that levels of LRRK1 and LRRK2 are reduced in dissected ventral midbrains of LRRK cDKO mice. While DA neuron-restricted LRRK cDKO mice of both sexes exhibit normal mortality and body weight, they develop age-dependent loss of DA neurons in the SNpc, as demonstrated by the progressive reduction of DA neurons in the SNpc of LRRK cDKO mice at the ages of 20 and 24 months but the unaffected number of DA neurons at the age of 15 months. Moreover, DA neurodegeneration is accompanied with increases of apoptosis and elevated microgliosis in the SNpc as well as decreases of DA terminals in the striatum, and is preceded by impaired motor coordination. Taken together, these findings provide the unequivocal evidence for the importance of LRRK in DA neurons and raise the possibility that LRRK2 mutations may impair its protection of DA neurons, leading to DA neurodegeneration in PD.

neuroscience↗

Estimation of in-vivo cerebrospinal fluid velocity using fMRI inflow effect

In vivo estimation of cerebrospinal fluid (CSF) velocity is crucial for understanding the glymphatic system and its potential role in neurodegenerative disorders such as Alzheimers disease and Parkinsons disease. Current cardiac or respiratory gated approaches, such as 4D flow MRI, cannot capture CSF movement in real time due to limited temporal resolution and in addition deteriorate in accuracy at low fluid velocities. Other techniques like real-time PC-MRI or time-spatial labeling inversion pulse are not limited by temporal averaging but have limited availability even in research settings. This study aims to quantify the inflow effect of dynamic CSF motion on functional magnetic resonance imaging (fMRI) for in vivo, real-time measurement of CSF flow velocity. We considered linear and nonlinear models of velocity waveforms and empirically fit them to fMRI data from a controlled flow experiment. To assess the utility of this methodology in human data, CSF flow velocities were computed from fMRI data acquired in eight healthy volunteers. Breath holding regimens were used to amplify CSF flow oscillations. Our experimental flow study revealed that CSF velocity is nonlinearly related to inflow effect-mediated signal increase and well estimated using an extension of a previous nonlinear framework. Using this relationship, we recovered velocity from in vivo fMRI signal, demonstrating the potential of our approach for estimating CSF flow velocity in the human brain. This novel method could serve as an alternative approach to quantifying slow flow velocities in real time, such as CSF flow in the ventricular system, thereby providing valuable insights into the glymphatic systems function and its implications for neurological disorders.

physiology↗

High-resolution structure of mouse radial spoke and its in-situ structure in ependymal cilia revealed by cryo-EM and cryo-ET

Radial spokes (RS) transmit mechanochemical signals between the central pair (CP) and axonemal dynein arms to coordinate ciliary motility. However, the high-resolution structure of mammalian RS remains missing. Here, we present the high-resolution cryo-EM structure of mouse RS head-neck complex in both monomer and dimer forms and reveal the intrinsic dynamics of the dimer. We also map the genetic mutations related to primary ciliary dyskinesia and asthenospermia on the head-neck complex. Moreover, we present the unprecedented cryo-ET and sub-tomogram averaging map of mouse ependymal cilia, whose beating creates unidirectional cerebrospinal fluid flow, and build the models for RS1-3, IDAs, and N-DRC. Strikingly, our cryo-ET map reveals the lack of IDA-b/c/e and the absence of tektin filaments within the A-tubule of doublet microtubules in ependymal cilia compared with mammalian respiratory cilia and sperm flagella. This tissue-specific feature may represent an evolutionary choice driven by the functional requirements on ependymal cilia. Our findings reveal the RS head-neck assembly mechanism, shed light on the coordinated rigid and elastic RS-CP interaction modes beneficial for the regulation of asymmetric ciliary beating, and also facilitate understandings on the etiology of ciliary dyskinesia-related ciliopathies.

biophysics↗

PENet: A phenotype encoding network for automatic extraction and representation of morphological discriminative features

Discriminative traits are important in biodiversity and macroevolution, but extracting and representing these features from huge natural history collections using traditional methods can be challenging and time-consuming. To fully utilize the collections and their associated metadata, it is urgent now to increase the efficiency of automatic feature extraction and sample retrieval. We developed a Phenotype Encoding Network (PENet), a deep learning-based model that combines hashing methods to automatically extract and encode discriminative features into hash codes. We tested the performance of PENet on six datasets, including a newly constructed beetle dataset with six subfamilies and 6566 images, which covers more than 60% of the genera in the family Scarabaeidae. PENet showed excellent performance in feature extraction and image retrieval. Two visualization methods, t-SNE, and Grad-CAM, were used to evaluate the representation ability of the hash codes. Further, by using the hash codes generated from PENet, a phenetic distance tree was constructed based on the beetle dataset. The result indicated the hash codes could reveal the phenetic distances and relationships among categories to a certain extent. PENet provides an automatic way to extract and represent morphological discriminative features with higher efficiency, and the generated hash codes serve as a low-dimensional carrier of discriminative features and phenotypic distance information, allowing for broader applications in systematics and ecology.

evolutionary biology↗

Functional divergences of natural variations of TaNAM-A1 controlling leaf senescence initiation during wheat grain filling

Leaf senescence is an essential physiological process related to grain yield potential and nutritional quality. Green leaf duration (GLD) after anthesis directly reflects the leaf senescence process and exhibits large genotypic differences in common wheat; however, the underlying gene regulatory mechanism is still lacking up to now. Here, we report TaNAM-A1 as the causal gene of major loci qGLD-6A for GLD during grain filling by map-based cloning. The role of TaNAM-A1 in regulating leaf senescence, spike length, and grain size was proved by transgenic assay and TILLING mutants analyses. Furthermore, the functional divergences among TaNAM-A1 three haplotypes were systematically evaluated. Wheat varieties with TaNAM-A1d (containing two mutations in CDS of TaNAM-A1) had longer GLD and advantages in yield-related traits than those with the wild type TaNAM-A1a. All three haplotypes were functional in transactivating the expression of genes involved in macromolecular degradation and mineral nutrient remobilization, with TaNAM-A1a the strongest activity and TaNAM-A1d the weakest. TaNAM-A1 modulates the expression of TaNAC016-3A and TaNAC-S-7A to trigger senescence initiation. TaNAC016-3A enhances TaNAM-A1 transcriptional activation ability by protein-protein interaction. Our study provides new insights into fine-tuning the leaf functional period and grain yield formation for wheat breeding under different geographical climatic conditions.

plant biology↗

Boosting BDNF in muscle rescues impaired in vivo axonal transport in a mouse model of DI-CMTC peripheral neuropathy

Charcot-Marie-Tooth disease (CMT) is a genetic peripheral neuropathy caused by mutations in many functionally diverse genes. The aminoacyl-tRNA synthetase (ARS) enzymes, which transfer amino acids to partner tRNAs for protein synthesis, represent the largest protein family genetically linked to CMT aetiology, suggesting pathomechanistic commonalities. Dominant intermediate CMT type C (DI-CMTC) is caused by YARS1 mutations driving a toxic gain-of-function in the encoded tyrosyl-tRNA synthetase (TyrRS), which is mediated by exposure of consensus neomorphic surfaces through conformational changes of the mutant protein. In this study, we first showed that human DI-CMTC-causing TyrRSE196K mis-interacts with the extracellular domain of the BDNF receptor TrkB, an aberrant association we have previously characterised for several mutant glycyl-tRNA synthetases linked to CMT type 2D (CMT2D). We then performed temporal neuromuscular assessments of YarsE196K mice modelling DI-CMT. We determined that YarsE196K homozygotes display a selective, age-dependent impairment in in vivo axonal transport of neurotrophin-containing signalling endosomes, phenocopying CMT2D mice. This impairment is replicated by injection of recombinant TyrRSE196K, but not TyrRSWT, into muscles of wild-type mice. Augmenting BDNF in DI-CMTC muscles, through injection of recombinant protein or muscle-specific gene therapy, resulted in complete axonal transport correction. Therefore, this work identifies a non-cell autonomous pathomechanism common to ARS-related neuropathies, and highlights the potential of boosting BDNF levels in muscles as a therapeutic strategy.

neuroscience↗

XClone: detection of allele-specific subclonal copy number variations from single-cell transcriptomic data

Somatic copy number alterations (CNAs) are major mutations that contribute to the development and progression of various cancers. Despite a few computational methods proposed to detect CNAs from single-cell transcriptomic data, the technical sparsity of such data makes it challenging to identify allele-specific CNAs, particularly in complex clonal structures. In this study, we present a statistical method, XClone, that strengthens the signals of read depth and allelic imbalance by effective smoothing on cell neighborhood and gene coordinate graphs to detect haplotype-aware CNAs from scRNA-seq data. By applying XClone to multiple datasets with challenging compositions, we demonstrated its ability to robustly detect different types of allele-specific CNAs and potentially indicate whole genome duplication, therefore enabling the discovery of corresponding subclones and the dissection of their phenotypic impacts.

bioinformatics↗

Epigenetic modifications mediate cultivar-specific root development and metabolic adaptation to nitrogen availability in wheat

The breeding of crops with improved nitrogen use efficiency (NUE) is crucial for sustainable agriculture. However, the role of epigenetic modification in the regulation of cultivar-specific responses to low nitrogen (LN) constraint is not well understood. Here, we analyzed the chromatin landscapes in roots, leaves, and seeds in two wheat cultivars (KN9204 and J411) that differ radically in NUE under normal and nitrogen-limited conditions. Transcriptional regulatory chromatin regions exhibited a clear cultivar-specificity between KN9204 and J411. Cultivar-specific regulation of nitrogen metabolism genes (NMGs) is linked to variation in histone modification levels, rather than differences in DNA sequence. Cultivar-specific histone modification regions were found to contribute to the genetic regulation of NUE-related traits, such as QTL locus of maximum root length of qMRL-7B. Furthermore, LN-induced H3K27ac and H3K27me3 dynamics enhanced root growth more in KN9204, while strengthened the nitrogen uptake system more in J411. Evidence from histone deacetylase inhibitor treatment and transgenic plants with loss-of-function of the H3K27me3 methyltransferase further showed that changes in epigenetic modifications can alter the strategy for root development and nitrogen uptake in response to LN constraint. Taken together, the results of our study highlight the importance of epigenetic regulation in mediating cultivar-specific root development and metabolic adaptation to LN in wheat.

plant biology↗

GenBank genomics highlight the genomic features, genetic diversity and regulation of morphological, metabolic and disease-resistance traits in Nicotiana tabacum

Nicotiana tabacum is a model organism in plant molecular and pathogenic research and has significant potential in the production of biofuels and active pharmaceutical compounds in synthetic biology. Because of the large allotetraploid genome of tobacco, its genomic features, genetic diversity and genetic regulation of many complex traits remain unknown. In this study, we present a nearly complete chromosome-scale assembly of N. tabacum and provide evidence that homoeologous exchange between subgenomes and epigenetic remodelling are likely mechanisms of genome stabilization and subgenome coordination following polyploidization. By leveraging GenBank-scale sequencing and phenotyping data from 5196 lines, geography at the continent scale, rather than types assigned on the basis of curing crop practices, was found to be the most important correlate of genetic structure. Using 178 marker{square}trait associations detected in genome-wide association analysis, a reference genotype-to-phenotype map was built for 39 morphological, developmental, and disease-resistance traits. A novel gene, auxin response factor 9 (Arf9), associated with wider leaves after being knocked out, was fine-mapped to a single nucleotide polymorphism (SNP). This point mutation alters the translated amino acid from Ala203 to Pro203, likely preventing homodimer formation during DNA binding. Our analysis also revealed signatures of positive and polygenic selection for multiple traits during the process of selective breeding. Overall, this study demonstrated the power of leveraging GenBank genomics to gain insights into the genomic features, genetic diversity, and regulation of complex traits in N. tabacum, laying a foundation for future research on plant functional genomics, crop breeding, and the production of biopharmaceuticals and biofuels.

genetics↗

Caltubin regulates microtubule stability via Ca2+-dependent mechanisms favouring neurite regrowth

Microtubule regulation is highly controlled in nerve regeneration. Caltubin, a novel Lymnaea stagnalis protein, contains putative EF-hand calcium-binding motifs and promotes neuronal outgrowth in Lymnaea and mouse. Here, we generated cell-permeable caltubin proteins to investigate mechanisms underlying this effect. We observed increased neurite extension and outgrowth following injury in caltubin-treated mouse neurons compared to vehicle controls. Purified caltubin bound -tubulin between its L391-V405 amino acids and promoted microtubule assembly. Caltubin competitively inhibited binding of tubulin tyrosine ligase, which catalyzes tubulin retyrosination, and increased the ratio of detyrosinated to tyrosinated tubulin. Our crystal structure analysis confirmed that caltubin has four Ca2+-binding EF-hand motifs, like calmodulin but has distinct peptide binding domains. Our work suggests a unique Ca2+-dependent regulatory mechanism of microtubule assembly by caltubin. This may represent an essential mechanism of axonal regulation, which may optimize its activity in response to various calcium states, both physiological and following injury.

cell biology↗

Neurofluid Coupling during Sleep and Wake States

Low-frequency changes in cerebral hemodynamics have recently been shown to drive cerebrospinal fluid (CSF) movement in the human brain during non-rapid eye movement (NREM) sleep and resting state wakefulness. However, whether the coupling strength between these neurofluids varies between wake and sleep states is not known. In addition, the principal origin (i.e., neuronal vs. systemic) of these slow cerebral hemodynamic oscillations in either state also remains unexplored. To investigate this, a wake/sleep study was conducted on eight young, healthy volunteers, concurrently acquiring neurofluid dynamics using functional Magnetic Resonance Imaging, neural activity using Electroencephalography, and non-neuronal systemic physiology with peripheral functional Near-Infrared Spectroscopy. Our results reveal that low-frequency cerebral hemodynamics and CSF movements are strongly coupled regardless of whether participants were awake or in light NREM sleep. Furthermore, it was also found that, while autonomic neural contributions are present only during light NREM sleep, non-neuronal systemic physiology influences neurofluid low-frquency oscillations in a significant way across both wake and sleep states. These results further our understanding regarding the low-frequency hemodynamic drivers of CSF movement in the human brain and could help inform the development of therapies for enhancing CSF circulation.

neuroscience↗

Overcoming the Blood-Brain Barrier for Gene Therapy via Systemic Administration of GSH-Responsive Silica Nanocapsules

CRISPR genome editing has demonstrated great potential to treat the root causes of many genetic diseases, including central nervous system (CNS) disorders. However, the promise of brain-targeted therapeutic genome editing relies on the efficient delivery of biologics bypassing the blood-brain barrier (BBB), which represents a substantial challenge in the development of CRISPR therapeutics. In this study, we created a library of GSH-responsive silica nanocapsules (SNCs) and screened them for brain targeting via systemic delivery of nucleic acids and CRISPR genome editors. In vivo studies demonstrated that systemically delivered SNCs conjugated with glucose and RVG peptide under glycemic control can efficiently bypass the intact BBB, enabling brain-wide delivery of various biologics (mRNA, Cas9 mRNA/sgRNA, and Cas9/sgRNA ribonucleoprotein) targeting both exogenous genes (i.e., Ai14 stop cassette) and disease-relevant endogenous genes (i.e., App and Th genes) in Ai14 reporter mice and wild-type mice, respectively. In particular, we observed up to 28% neuron editing via systemic delivery of Cre mRNA in Ai14 mice, up to 6.1% amyloid precursor protein (App) gene editing (resulting in 19.1% reduction in the expression level of intact APP), and up to 3.9% tyrosine hydroxylase (Th) gene editing (resulting in 30.3% reduction in the expression level of TH) in wild-type mice. This versatile SNC nanoplatform may offer a novel strategy for the treatment of CNS disorders including Alzheimers, Parkinsons, and Huntingtons disease.

neuroscience↗

Transposable elements orchestrate subgenome-convergent and -divergent transcription in common wheat

The success of common wheat as the global staple crop is derived from genome diversity and redundancy as a result of allopolyploidization [1-3], giving rise to the major question how the divergent and convergent transcription among different subgenomes are achieved and harmonized in a single cell. The regulatory information is largely encoded in DNA regulatory elements (REs) interpreted by sequence specific transcription factors (TFs). Here, we created a catalog of genome-wide TF-binding sites (TFBS) to assemble an extensive wheat regulatory network comprising connections among 189 TFs and 3,714,431 REs, which enhances the understanding of wheat regulatory mechanisms on an unprecedented scale. A significant fraction of subgenome-divergent TFBS are derived from recent subgenome-asymmetric expansion of particular transposable element (TE) families. In contrary, TFBS derived from ancient TE expansion largely underwent parallel purifying selection during independent evolution of each subgenome, despite extensive unbalanced turnover of flanking TEs. Altogether, the subgenome-convergent and -divergent regulation in common wheat is orchestrated via differential evolutionary selection on paleo- and neo-TEs.

bioinformatics↗

DeepCIP: a multimodal deep learning method for the prediction of internal ribosome entry sites of circRNAs

MotivationCircular RNAs (circRNAs) have been found to have the potential to code proteins. Internal ribosome entry sites (IRESs) are key RNA regulatory elements for the translation of proteins by circRNAs through a cap-independent mechanism. IRES can be identified by bicistronic assay, but the method is time-consuming and laborious. Therefore, it is important to develop computational methods for facilitating IRES identification, evaluation, and design in circRNAs. ResultsIn this study, we proposed DeepCIP, a multimodal deep learning approach for circRNA IRES prediction, by exploiting both sequence and structure information. As far as we know, DeepCIP is the first predictor for circRNA IRESs, which consists of an RNA processing module, an S-LSTM module, a GCN module, a feature fusion module, and an ensemble module. The comparative studies show that DeepCIP outperforms other comparative methods and justify the effectiveness of the sequence model and structure model of DeepCIP for extracting features. We found that the integration of structural information on the basis of sequence information effectively improves predictive performance. For the real circRNA IRES prediction, DeepCIP also outperforms other methods. DeepCIP may facilitate the study of the coding potential of circRNAs as well as the design of circRNA drugs. DeepCIP as a standalone program is freely available at https://github.org/zjupgx/DeepCIP.

bioinformatics↗

Inhibitory effects of GT0918 on acute lung injury and the molecular mechanisms of anti-inflammatory response

Coronavirus disease 2019 (COVID-19) has caused the public health crisis in the whole world. Anti-androgens block severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry and protect against severe clinical COVID-19 outcomes. GT0918, a novel androgen receptor antagonist, accelerated viral clearance and increased recovery rate in outpatients by blocking SARS-CoV-2 infection though down-regulating ACE2 and TMPRSS2 expression. Further clinical study showed that GT0918 reduced mortality rate and shortened hospital stay in hospitalized COVID-19 patients. GT0918 also exhibits protective efficacy in severe COVID-19 patient in critical care. However, the mechanism of GT0918 treatment for severe COVID-19 disease is unknown. Here, we found GT0918 decreased the expression and secretion of proinflammatory cytokines through NF-{kappa}B signaling pathway. The acute lung injury induced by LPS or Poly(I:C) was also attenuated in GT0918-treated mice, compared with vehicle control group. Moreover, GT0918 elevated the NRF2 protein level but not mRNA transcription activity. GT0918 induced proinflammatory cytokines downregulation was partially dependent on NRF2. In conclusion, our data demonstrate that GT0918 reduced cytokine release and suppressed inflammatory responses through inhibiting NF-{kappa}B signaling and activating NRF2. GT0918 is not only effective for treatment of mild to moderate COVID-19 patients, but also a potential therapeutic drug for severe COVID-19 patients by reducing the risk of cytokine storm and acute respiratory distress syndrome.

cell biology↗

A G protein coupled receptor like protein systematically modulates nutrient-growth by Ca2+ mediated phosphatidylcholine perception during evolutionary adaptation

Nutrients are important for growth in both plants and animals, uncovering of signaling pathway in nutrients determined growth is essential. Here we cloned TaPCGR1-3B (Phospholipid Coordinated Growth and nutrients Response 1), controlled by SNPs on alternative splicing and transcription factors binding, conferring nitrogen deficiency response. TaPCGR1-3B was localized in plasma membrane and endoplasmic reticulum of meristem cell. Nitrogen deprivation stimulated interaction of TaPCGR1-3B with G protein alpha subunit and phospholipase C 9, which was inhibited by phosphatidylcholine, to trigger Ca2+ signaling and inhibit normal growth. Knockdown of TaPCGR1 rescued the growth inhibition caused by nutrient deficient conditions by modulation of phosphatidylcholine induced growth gene expression through Ca2+ signaling disruption. Modulating of phosphatidylcholine mediated TaPCGR1 activity thus tightly regulated growth through Ca2+ signaling.

genetics↗

Pathogen-Host Adhesion between SARS-CoV-2 S Proteins from Different Variants and Human ACE2 Probed at Single-Molecule and Single-Cell Levels

Pathogen-Host adhesion is considered the first step of infection for many pathogens such as bacteria and virus. The binding of the receptor binding domain (RBD) of SARS-CoV-2 Spike protein (S protein) onto human angiotensin-converting enzyme 2 (ACE2) is considered as the first step for the SARS-CoV-2 to adhere onto the host cells during the infection. Within three years, a number of variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been found all around the world. Here, we investigated the adhesion of S Proteins from different variants and ACE2 using atomic force microscopy (AFM)-based single-molecule force spectroscopy (SMFS) and single-cell force spectroscopy (SCFS). We found that the unbinding force and binding probability of the S protein from Delta variant to the ACE2 was the highest among the variants tested in our study at both single-molecule and single-cell levels. Molecular dynamics simulation showed that ACE2-RBD (Omicron) complex is destabilized by the E484A and Y505H mutations and stabilized by S477N and N501Y mutations, when compared with Delta variant. In addition, a neutralizing antibody, produced by immunization with wild type RBD of S protein, could effectively inhibit the binding of S proteins from wild type, Delta and Omicron variants onto ACE2. Our results provide new insight for the molecular mechanism of the adhesive interactions between S protein and ACE2 and suggest that effective monoclonal antibody can be prepared using wild type S protein against the different variants.

biophysics↗