Biology subjects

Zhang, R.

Publications and source records attributed to Zhang, R..

At least 379 records · Page 21Linked to original sources

bioRxiv2022

O-GlcNAcylation promotes YTHDF1 cytosolic localization and colorectal cancer tumorigenesis

O-linked N-acetylglucosamine (O-GlcNAc) is an emerging post-translation modification that couples metabolism with cellular signal transduction by crosstalking with phosphorylation and ubiquitination to orchestrate various biological processes. Herein we show that it modifies the N6-methyladenosine (m6A)-mRNA reader YTHDF1 and fine-tunes its nuclear translocation by the exportin protein Crm1. First we present evidence that YTHDF1 interacts with the sole O-GlcNAc transferase (OGT). Second, we verified the YTHDF1 O-GlcNAcylation sites to be Ser196/Ser197/Ser198, as described in previous numerous chemoproteomic studies. Then we constructed the O-GlcNAc-deficient YTHDF1-S196AS197FS198A (AFA) mutants, which significantly attentuated O-GlcNAc signals. Moreover, we revealed that YTHDF1 is a nucleocytoplasmic protein, whose nuclear export is mediated by Crm1. Furthermore, O-GlcNAcylation increases the cytosolic portion of YTHDF1 by enhancing binding with Crm1, thus upregulating the downstream target (e.g. c-Myc) expression. Molecular dynamics simulations suggest that O-GlcNAcylation at S197 might promote the binding between the nuclear export signal motif and Crm1 through increasing hydrogen bonding. Mouse xenograft assays further demonstrate that YTHDF1-AFA mutants decreased the colon cancer mass and size via decreasing c-Myc expression. In sum, we found that YTHDF1 is a nucleocytoplasmic protein, whose cytosolic localization is dependent on O-GlcNAc modification. We propose that the OGT-YTHDF1-c-Myc axis might underlie colorectal cancer tumorigenesis.

biochemistry↗

bioRxiv2022

Identifying genes and pathways linking astrocyte regional specificity to Alzheimer's disease susceptibility

Astrocytes have been shown to play a central role in Alzheimers Disease (AD). However, the genes and biological pathways underlying disease manifestation are unknown, and it is unclear whether regional molecular differences among astrocytes contribute to regional specificity of disease. Here, we began to address these challenges with integrated experimental and computational approaches. We constructed a human astrocyte-specific functional gene network using Bayesian integration of a large compendium of human functional genomics data, as well as regional astrocyte gene expression profiles we generated in the mouse. This network identifies likely region-specific astrocyte pathways that operate in healthy brains. We leveraged our findings to compile genome-wide astrocyte-associated disease-gene predictions, employing a novel network-guided differential expression analysis (NetDIFF). We also used this data to predict a list of astrocyte-expressed genes mediating region-specific human disease, using a network-guided shortest path method (NetPATH). Both the network and our results are publicly available using an interactive web interface at http://astrocyte.princeton.edu. Our experimental and computational studies propose a strategy for disease gene and pathway prediction that may be applied to a host of human neurological disorders.

systems biology↗

bioRxiv2022

Three-dimensional molecular architecture of mouse organogenesis

Mammalian embryos have sophisticated cell organizations that are orchestrated by molecular regulation at cellular and tissue level. It has recently been appreciated that the cells that make up the animal body themselves harbor significant heterogeneity in the context of both cellular and particularly spatial dimension. However, current spatial transcriptomics profiling of embryonic tissues either lack three-dimensional representation or are restricted to limited depth and organs. Here, we reported a holistic spatial transcriptome atlas of all major organs at embryonic day 13.5 of mouse embryo and delineated a 3D rendering of the molecular regulation of embryonic patterning. By integrating with corresponding single-cell transcriptome data, the spatial organogenesis atlas provides rich molecular annotation of the dynamic organ nature, spatial cellular interaction, embryonic axes and divergence of cell fates underlying mammalian development, which would pave the way for precise organ-engineering and stem-cell based regenerative medicine.

developmental biology↗

bioRxiv2022

Engineering CAR-NK cells targeting CD33 with concomitant extracellular secretion of anti CD16 antibody revealed superior antitumor effects toward myeloid leukemia

Acute myeloid leukemia (AML) is a common form of acute leukemia and current drugs are overall unsatisfactory. In the present study, we report an immune cell therapy strategy by employing genetically-modified bifunctional CAR-NK cells that combines efficient targeting of AML cells via the CD33 molecule with the concomitant stimulation of NK cell cytotoxicity through the expression and extracellular secretion of anti-CD16 antibody (B16) that binds back to the FC receptor of NK cells. Comparing to CAR-NK cells that target CD33 only, the bifunctional CD33/B16 CAR-NK cells showed superior killing efficiency toward AML cells in vitro, which increased about 4 times based on the number of cells needed to achieve 80% killing activity. In vivo study with xenograft model also revealed effective clearance of leukemic cells and much longer survival - no relapse or death for at least 60 days. In addition, the safety of CAR-NK is not changed with additional expression of B16 as determined by the release of cytokines. These data revealed a promising CAR-NK approach to treat AML patients, which may improve CAR-NK based treatment in general and have potential applications to deal with other tumors as well.

immunology↗

bioRxiv2022

Controlled Hydrogen Sulfide Delivery to Enhance Cell Survival in Bone Tissue Engineering

The increased local concentration of calcium ions (Ca2+) and phosphate (Pi), a natural body process for bone healing and remodeling, as well as local delivery of these ions as signaling molecules by synthetic bone graft substitutes, may lead to cytotoxic ion levels that can result in Ca2+/ Pi mitochondria overload, oxidative stress, and cell death. In this research, the effect of H2S as a cytoprotective signaling molecule to increase the tolerance of mesenchymal stem cells (MSCs) in the presence of cytotoxic level of Ca2+/Pi was evaluated. Different concentrations of sodium hydrogen sulfide (NaSH), a fast-releasing H2S donor, were exposed to cells in order to evaluate the influence of H2S on MSC proliferation. The results suggested that a range of NaSH (i.e., 0.25 - 4 mM NaSH) was non-cytotoxic and could improve cell proliferation and differentiation in the presence of cytotoxic levels of Ca2+ (32 mM) and/or Pi (16 mM). To controllably deliver H2S over time, a novel donor molecule in thioglutamic acid (GluSH) was synthesized and evaluated for its H2S release profile. Excitingly, GluSH successfully maintained cytoprotective level of H2S over 7 days. Furthermore, MSCs exposed to cytotoxic Ca2+/Pi concentrations in the presence of GluSH were able to thrive and differentiate into osteoblasts. These findings suggest that the incorporation of a sustained H2S donor such as GluSH into CaP-based bone substitutes can facilitate considerable cytoprotection making it an attractive option for complex bone regenerative engineering applications.

bioengineering↗

bioRxiv2022

NSC-derived exosomes enhance therapeutic effects of NSC transplantation on cerebral ischemia in mice

AbstractTransplantation of neural stem cells (NSCs) has been proved to promote functional rehabilitation of brain lesions including ischemic stroke. However, the therapeutic effects of NSC transplantation is limited by the low survival and differentiation rates of NSCs due to the harsh environment in the brain after ischemic stroke. Here, we employed NSCs derived from human induced pluripotent stem cells (iPSCs) together with exosomes extracted from NSCs to treat cerebral ischemia induced by middle cerebral artery occlusion/reperfusion (MCAO/R) in mice. The results showed that NSC-derived exosomes significantly reduced the inflammatory response, alleviated oxidative stress after NSC transplantation, and facilitated NSCs differentiation in vivo. The combination of NSCs with exosomes ameliorated the injury of brain tissue including cerebral infarct, neuronal death and glial scarring, and promoted the motor function recovery. To explore the underlying mechanisms, we analyzed the miRNA profiles of NSC-derived exosomes and the potential downstream genes. Our study provided the rationale for the clinical application of NSC-derived exosomes as a supportive adjuvant for NSC transplantation after stroke.

neuroscience↗

bioRxiv2022

Differential bending stiffness of the bacterial flagellar hook under counterclockwise and clockwise rotations

The bacterial hook, as a universal joint coupling rotation of the flagellar motor and the filament, is an important component of the flagellum that propels the bacteria to swim. The mechanical properties of the hook are essential for the flagellum to achieve normal functions. In multi-flagellated bacteria such as Escherichia coli, the hook must be compliant so that it can bend for the filaments to form a coherently rotating bundle to generate the thrust when the motor rotates counterclockwise (CCW), yet it also must be rigid so that the bundle can disrupt for the bacteria to tumble to change swimming direction when the motor rotates clockwise (CW). Here, by combining an elastic rod model with high-resolution bead assay to accurately measure the bending stiffness of the hook under CCW or CW rotation in vivo, we elucidate how the hook accomplishes this dual functionality: the hook stiffens under CW rotation, with bending stiffness under CW rotation twice as large as that under CCW rotation. This enables a robust run-and-tumble swimming motility for multi-flagellated bacteria.

biophysics↗

bioRxiv2022

Ratio-based quantitative multiomics profiling using universal reference materials empowers data integration

Multiomics profiling is a powerful tool to characterize the same samples with complementary features orchestrating the genome, epigenome, transcriptome, proteome, and metabolome. However, the lack of ground truth hampers the objective assessment of and subsequent choice from a plethora of measurement and computational methods aiming to integrate diverse and often enigmatically incomparable omics datasets. Here we establish and characterize the first suites of publicly available multiomics reference materials of matched DNA, RNA, proteins, and metabolites derived from immortalized cell lines from a family quartet of parents and monozygotic twin daughters, providing built-in truth defined by family relationship and the central dogma. We demonstrate that the "ratio"-based omics profiling data, i.e., by scaling the absolute feature values of a study sample relative to those of a concurrently measured universal reference sample, were inherently much more reproducible and comparable across batches, labs, platforms, and omics types, thus empower the horizontal (within-omics) and vertical (cross-omics) data integration in multiomics studies. Our study identifies "absolute" feature quantitation as the root cause of irreproducibility in multiomics measurement and data integration, and urges a paradigm shift from "absolute" to "ratio"-based multiomics profiling with universal reference materials.

systems biology↗

bioRxiv2022

Fear of missing out (FOMO) associates with reduced cortical thickness in core regions of the posterior default mode network and higher levels of problematic smartphone and social media use

Fear of missing out (FOMO) promotes the desire or urge to stay continuously connected with a social reference group and updated on their activities, which may result in escalating and potentially addictive smartphone and social media use. The present study aimed to determine whether the neurobiological basis of FOMO encompasses core regions of the reward or social brain, and the associations with the level of problematic smartphone or social media use. We capitalized on a dimensional neuroimaging approach to examine cortical thickness and subcortical volume associations in a comparably large sample of healthy young individuals (n = 167). Meta-analytic network and behavioral decoding were employed to further characterize the identified regions. Higher levels of FOMO associated with lower cortical thickness in the precuneus. In contrast, no associations between FOMO and variations in striatal morphology were observed. Meta-analysis decoding revealed that the identified precuneus region exhibited a strong functional interaction with the default mode network (DMN) engaged in social cognitive and self-referential domains. Together the present findings suggest that individual variations in FOMO are associated with the brain structural architecture of the right precuneus, a core hub within a large-scale functional network resembling the DMN involved in social and self-referential processes. FOMO may promote escalating social media and smartphone use via social and self-referential processes rather than reward-related processes per se.

neuroscience↗

bioRxiv2022

Neural signatures of second language proficiency in narrative processing.

Making sense of speech in a second language relies on multiple abilities. Differences in brain activity related to proficiency in language tasks have often been attributed to processing demands. However, during naturalistic narrative comprehension, listeners at different proficiency levels may form different representations of the same speech. We hypothesized that the synchronization of these representations across people could thus be used to measure second-language proficiency. Using a searchlight shared response model, we found that highly proficient participants showed synchronization in regions similar to those of native speakers, including in the default mode network and in the lateral prefrontal cortex. In contrast, participants with low proficiency showed more synchronization in auditory cortex and word-level semantic processing areas in the temporal lobe. Moderate proficiency showed the greatest neural diversity, suggesting lower consistency in the source of this partial proficiency. Based on these synchronization differences, we were able to reliably classify the proficiency level or predict behavioral performance on an independent English test in held-out participants, suggesting the identified neural systems represented proficiency-sensitive information that was generalizable to other individuals. These findings suggest higher second-language proficiency leads to a more native-like neural processing of naturalistic language, including in systems beyond the cognitive control network or the core language network. HighlightsO_LINeural synchronization in second-language speech processing reflects proficiency. C_LIO_LIHigh-proficiency individuals neurally resemble native speakers. C_LIO_LILow-proficiency individuals are synchronized in perceptual and word semantics areas. C_LIO_LIProficiency level can be predicted using neural synchronization signatures. C_LI

neuroscience↗

bioRxiv2022

MAP4Ks inhibition promotes retinal neuron regeneration from Muumlller glia in adult mice

Mammalian Muller glia (MG) possess limited regenerative capacities. However, the intrinsic capacity of mammalian MG to transdifferentiate to generate mature neurons without transgenic manipulations remains speculative. Here we show that MAP4K4, MAP4K6 and MAP4K7, which are conserved Misshapen subfamily of ste20 kinases homologs, repress YAP activity in mammalian MG and therefore restrict their ability to be reprogrammed. However, by treating with a small molecule inhibitor of MAP4K4/6/7, mouse MG regain their ability to proliferate and enter into a retinal progenitor cell (RPC)-like state after NMDA-induced retinal damage; such plasticity was lost in YAP knockout MG. Moreover, spontaneous trans-differentiation of MG into retinal neurons expressing both amacrine and retinal ganglion cell (RGC) markers occurs after inhibitor withdrawal. Taken together, these findings suggest that MAP4Ks block the reprogramming capacity of MG in a YAP-dependent manner in adult mammals, which provides a novel avenue for the pharmaceutical induction of retinal regeneration in vivo.

neuroscience↗

bioRxiv2022

Transfer Entropy Based Causality from Head Motion to Eye Movement for Visual Scanning in Virtual Driving

Visual scanning is achieved by eye movement control for visual information acquisition and cognitive processing, which plays a critical role in undertaking common sensorimotor tasks such as driving. The specific coordination of the head and eyes, with head motions temporally preceding eye movements, is an important human behavior to make a key contribution to goal-directed visual scanning and sensorimotor driving. In this paper, we put forward a proposal of philosophy that this specific coordination of the head and eyes essentially indicates a unidirectional causality from head motion to eye movement. We propose to investigate transfer entropy for defining a quantitative measure of this unidirectional head-eye causality. A normalized version of the proposed causality measure is introduced for taking a role as an assessment proxy of driving. The plain transfer entropy-based definition has shown its statistical significance as the measure of causality and, the normalized version has demonstrated its good effectiveness for the evaluation of driving performance, with the verification in virtual reality-based psychophysical studies. This paper successfully suggests that the quantitative exploitation of causality based on the specific coordination of the head and eyes offers an effective approach to behaviometrics of visual scanning and sensorimotor activity. Author summaryThe coordination of head and eyes always exists in everyday sensorimotor driving tasks. Specifically, in goal-directed tasks, preparatory head motions guide eye movements to obtain and process relevant visual information for interacting with the surrounding environment. That is, the specific coordination of head and eyes involving head motions temporally preceding eye movement provides a mechanism for drivers to rely on prior knowledge for performing the tasks. As a matter of fact, this specific coordination of head and eyes essentially indicates, theoretically, a unidirectional causality from head motion to eye movement, leading to our proposal of causality philosophy. In this paper, an information-theoretic tool, transfer entropy, is exploited to capture the complex relationship between head motion and eye movement for obtaining the proposed measure of unidirectional causality. Furthermore, considering that the specific coordination of the head and eyes reflects the attention and cognitive state affecting the performance of sensorimotor tasks, we develop a normalized unidirectional causality measure as a proxy for the evaluation of driving performance. Psychophysical studies for goal-directed driving tasks are conducted based on virtual reality experimentation. Extensive results demonstrate a statistically significant correlation between the proposed normalized measure of causality and driving performance, which may provide a new and effective avenue for behaviometric applications. Practically, the merit of our proposed causality philosophy is that it is simple but effective, for obtaining an evaluation of the attentional and cognitive processes in driving tasks.

animal behavior and cognition↗

bioRxiv2022

Bacillus velezensis SQR9 sways the rhizosphere community and its sociality toward cooperation and plant growth promotion

According to the Lotka-Volterra competition model, intraspecific competition in plant-associated microbial communities should be stronger than interspecific competition. However, there is limited information on whether microbial communities follow this pattern and how disturbance by a newcomer affects them. Given the increasing popularity of probiotics, filling this knowledge gap could help guide future coexistence research. Here, we show that inoculation with a known probiotic, B. velezensis SQR9 shifts species co-occurrence patterns by decreasing the diversity of more distant species and promoting the growth of more closely related species, especially within the Bacillus community. By testing the sociality of Bacillus rhizosphere isolates, we then demonstrated that SQR9 increases the frequency of cooperative interactions in the Bacillus community, which may contribute to the promotion of plant growth. Finally, we provide an ecosystem framework comprising the strains genetic relatedness, metabolic niche space and social compatibility for the efficient and reliable assembly of Bacillus consortia. These findings shed new light on the ecological mechanisms underlying the beneficial effects of probiotics on host fitness.

microbiology↗

bioRxiv2022

Seeing the future: connectome strength and network efficiency in visual network predict individual ability of episodic future thinking

Episodic future thinking (EFT) refers to the critical ability that people construct vivid mental imagery about future events and pre-experience it, which helps with individual and group decision-making. Although EFT is generally believed to have a visual nature by theorists, little neuroscience evidence had been provided to verify this assumption. Here, by employing the approach of connectome-based predictive modeling (CPM) and graph-theoretical analysis, we analyzed resting-state functional brain image from 191 participants to predict their variability of EFT ability (leave-one-out cross-validation), and validated the results by applying different parcellation schemas and feature selection thresholds. At the connectome strength level, CPM-based analysis revealed that EFT ability could be predicted by the connectome strength of visual network. Further at the network level, graph-theoretical analysis showed that EFT ability could be predicted by the network efficiency of visual network. Moreover, these findings were replicated using different parcellation schemas and feature selection thresholds. These results robustly and collectively supported the visual network being the neural substrates underlying EFT ability from a comprehensive perspective of resting-state functional connectivity strength and the neural network. This study provides indications on how the function of visual network supports EFT ability, and helps to understand the EFT ability from a neural basis perspective.

neuroscience↗

bioRxiv2022

Curation of the Deep Green list of unannotated green lineage proteins to enable structural and functional characterization

An explosion of sequenced genomes and predicted proteomes enabled by low cost deep sequencing has revolutionized biology. Unfortunately, protein functional annotation is more complex, and has not kept pace with the sequencing revolution. We identified unannotated proteins in three model organisms representing distinct parts of the green lineage (Viridiplantae); Arabidopsis thaliana (dicot), Setaria viridis (monocot), and Chlamydomonas reinhardtii (Chlorophyte alga). Using similarity searching we found the subset of unannotated proteins that were conserved between these species and defined them as Deep Green proteins. Informatic, genomic, and structural predictions were leveraged to begin inferring functional information about Deep Green genes and proteins. The Deep Green set was enriched for proteins with predicted chloroplast targeting signals that are predictive of photosynthetic or plastid functions. Strikingly, structural predictions using AlphaFold and comparisons to known structures show that a significant proportion of Deep Green proteins may possess novel protein tertiary structures. The Deep Green genes and proteins provide a starting resource of high value targets for further investigation of potentially new protein structures and functions that are conserved in the green lineage.

plant biology↗

bioRxiv2022

HY5 Regulates GLK and GNC Transcription Factors to Orchestrate Photomorphogenesis in Arabidopsis thaliana

Light induced de-etiolation is an important aspect of seedling photomorphogenesis. GOLDEN2 LIKE (GLK) transcriptional regulators are involved in chloroplast development, but to what extent they participate in photomorphogenesis is not clear. Here we show that ELONGATED HYPOCOTYL5 (HY5) binds to GLK promoters to activate their expression, and also interacts with GLK proteins. Chlorophyll content in the de-etiolating Arabidopsis seedlings of the hy5 glk2 double mutants was lower than that in hy5 single mutant. GLKs inhibited hypocotyl elongation, and the phenotype could superimpose on the hy5 phenotype. Correspondingly, GLK2 regulates the expression of photosynthesis and cell elongation genes partially independent of HY5. Before exposed to light, the accumulation of GLK proteins was regulated by DE-ETIOLATED 1 (DET1), while also affected (especially for GLK1) transcriptionally by HY5. The enhanced etioplast development and photosystem gene expression observed in det1 mutant were attenuated in det1 glk2 double mutant. Our study reveals that GLKs act down-stream of HY5 and likely cooperate with HY5 and DET1, to orchestrate multiple developmental traits during the light-induced skotomorphogenesis to photomorphogenesis transition in Arabidopsis. One-sentence summaryGLK and GNC act downstream of HY5, and cooperate with HY5 and DET1, to regulate both chloroplast development and hypocotyl elongation during the transition from skotomorphogenesis to photomorphogenesis.

plant biology↗

bioRxiv2022

Quartet DNA reference materials and datasets for comprehensively evaluating germline variants calling performance

Current methods for evaluating the accuracy of germline variant calls are restricted to easy-to-detect high-confidence regions, thus ignoring a substantial portion of difficult variants beyond the benchmark regions. We established four DNA reference materials from immortalized cell lines derived from a Chinese Quartet including parents and monozygotic twins. We integrated benchmark calls of 4.2 million small variants and 15,000 structural variants from multiple platforms and bioinformatic pipelines for evaluating the reliability of germline variant calls inside the benchmark regions. The genetic built-in-truth of the Quartet family design not only improved sensitivity of benchmark calls by removing additional false positive variants with apparently high quality, but also enabled estimation of the precision of variants calls outside the benchmark regions. Batch effects of variant calling in large-scale DNA sequencing efforts can be effectively identified with the concurrent use of the Quartet DNA reference materials along with study samples, and can be alleviated by training a machine learning model with the Quartet reference datasets to remove potential artifact calls. Matched RNA and protein reference materials were also established in the Quartet project, thereby enabling benchmark calls constructed from DNA reference materials for evaluation of variants calling performance on RNA and protein data. The Quartet DNA reference materials from this study are a resource for objective and comprehensive assessment of the accuracy of germline variant calls throughout the whole-genome regions.

bioinformatics↗

bioRxiv2022

Quartet RNA reference materials and ratio-based reference datasets for reliable transcriptomic profiling

As an indispensable tool for transcriptome-wide analysis of differential gene expression, RNA sequencing (RNAseq) has demonstrated great potential in clinical applications. However, the lack of multi-group RNA reference materials of biological relevance and the corresponding reference datasets for assessing the reliability of RNAseq hampers its wide clinical applications wherein the underlying biological differences among study groups are often small. As part of the Quartet Project for quality control and data integration of multiomic profiling, we established four RNA reference materials derived from immortalized B-lymphoblastoid cell lines from four members of a monozygotic twin family. Additionally, we constructed ratio-based transcriptome-wide reference datasets using multi-batch RNAseq datasets, providing "ground truth" for benchmarking. Moreover, Quartet-sample-based quality metrics were developed for assessing reliability of RNAseq technology in terms of intra-batch proficiency and cross-batch reproducibility. The small intrinsic biological differences among the Quartet samples enable sensitive assessment of performance of transcriptomic measurements. The Quartet RNA reference materials combined with the reference datasets can be served as unique resources for assessing data quality and improving reliability of transcriptomic profiling.

genetics↗