Biology subjects

Lu, Z.

Publications and source records attributed to Lu, Z..

At least 145 records · Page 8Linked to original sources

bioRxiv2023

Targeting adipocyte ESRRA promotes osteogenesis and vascular formation in adipocyte-rich bone marrow

Ectopic bone marrow adipocytes (BMAds) accumulation occurring under diverse pathophysiological conditions leads to bone deterioration. Estrogen-related receptor (ESRRA) is a key regulator responding to metabolic stress. Here, we show that adipocyte-specific ESRRA deficiency rescues osteogenesis and vascular formation in adipocyte-rich bone marrow due to estrogen deficiency or obesity. Mechanistically, adipocyte ESRRA interferes with E2/ESR1 signaling resulting in transcriptional repression of secreted phosphoprotein 1 (Spp1); and positively modulates Leptin expression by binding to its promoter. ESRRA abrogation results in enhanced SPP1 and decreased LEPTIN secretion from both visceral adipocytes and BMAds, concertedly dictating bone marrow stromal stem cell fate commitment and restoring type H vessel formation, constituting a feed-forward loop for bone formation. Pharmacological inhibition of ESRRA protects obese mice against bone loss and high marrow adiposity. Thus, our findings highlight a therapeutic approach via targeting adipocyte ESRRA to preserve bone formation especially in detrimental adipocyte-rich bone milieu. Graphic abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/552932v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@1132da3org.highwire.dtl.DTLVardef@19342aorg.highwire.dtl.DTLVardef@afe8d7org.highwire.dtl.DTLVardef@dfb1f9_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2023

The roles of RNA editing in cancer immunity through interacting with interferon

The interferon-activated tumor innate immunity can be primed by specific double-stranded RNA (dsRNA) sensors upon stimulation. A-to-I RNA editing in the dsRNA regions can have a potential function to regulate interferon-related cancer immunity. A systematical analysis of both the editing enzyme and specific enriched editing region in patients, tissues, and cell lines is performed to reveal the underlying mechanisms. We then validate the preferred editing of dsRNA regions, identify the hyper-editing in severe tumors, and discover the negative effect of editing on cancer immunity. Specifically, RNA editing acts as an inhibitor of PKR- and MDA5-related interferon pathways through the regulations of miRNAs and RNA-binding proteins and the deactivation of dsRNA sensors. With the alteration of interferons, subsequently, RNA editing represses the infiltration of CD8 and CD4 T cells and reduces the sensitivities of cancer drugs, such as cisplatin. These analyses on A-to-I RNA editing can improve the knowledge of tumorigenesis, immunology, and cancer-targeted immunotherapy. HighlightsO_LIThe preferred dsRNA region for RNA editing is validated. C_LIO_LIUpregulation of RNA editing in severe tumors is discovered. C_LIO_LIRNA editing inhibits PKR- and MDA5-related cancer immunity. C_LIO_LIRNA editing represses the infiltration of CD8 and CD4 T cells. C_LIO_LIRNA editing reduces the sensitivities of cancer drugs. C_LI

bioinformatics↗

bioRxiv2023

Expansion of profibrotic monocyte-derived alveolar macrophages in patients with persistent respiratory symptoms and radiographic abnormalities after COVID-19

As many as 10-30% of the over 760 million survivors of COVID-19 develop persistent symptoms, of which respiratory symptoms are among the most common. To understand the cellular and molecular basis for respiratory PASC, we combined a machine learning based analysis of lung computed tomography (CT) with flow cytometry, single-cell RNA-sequencing analysis of bronchoalveolar lavage fluid and nasal curettage samples, and alveolar cytokine profiling in a cohort of thirty-five patients with respiratory symptoms and radiographic abnormalities more than 90 days after infection with COVID-19. CT images from patients with PASC revealed abnormalities involving 73% of the lung, which improved on subsequent imaging. Interstitial abnormalities suggestive of fibrosis on CT were associated with the increased numbers of neutrophils and presence of profibrotic monocyte-derived alveolar macrophages in BAL fluid, reflecting unresolved epithelial injury. Persistent infection with SARS-CoV-2 was identified in six patients and secondary bacterial or viral infections in two others. These findings suggest that despite its heterogenous clinical presentations, respiratory PASC with radiographic abnormalities results from a common pathobiology characterized by the ongoing recruitment of neutrophils and profibrotic monocyte-derived alveolar macrophages driving lung fibrosis with implications for diagnosis and therapy.

immunology↗

bioRxiv2023

Prolonged exposure to lung-derived cytokines is associated with inflammatory activation of microglia in patients with COVID-19

Neurological impairment is the most common finding in patients with post-acute sequelae of COVID-19. Furthermore, survivors of pneumonia from any cause have an elevated risk of dementia1-4. Dysfunction in microglia, the primary immune cell in the brain, has been linked to cognitive impairment in murine models of dementia and in humans5. Here, we report a transcriptional response in human microglia collected from patients who died following COVID-19 suggestive of their activation by TNF-[a] and other circulating pro-inflammatory cytokines. Consistent with these findings, the levels of 55 alveolar and plasma cytokines were elevated in a cohort of 341 patients with respiratory failure, including 93 unvaccinated patients with COVID-19 and 203 patients with other causes of pneumonia. While peak levels of pro-inflammatory cytokines were similar in patients with pneumonia irrespective of etiology, cumulative cytokine exposure was higher in patients with COVID-19. Corticosteroid treatment, which has been shown to be beneficial in patients with COVID-196, was associated with lower levels of CXCL10, CCL8, and CCL2--molecules that sustain inflammatory circuits between alveolar macrophages harboring SARS-CoV-2 and activated T cells7. These findings suggest that corticosteroids may break this cycle and decrease systemic exposure to lung-derived cytokines and inflammatory activation of microglia in patients with COVID-19.

immunology↗

bioRxiv2023

Origin of eukaryotic-like Vps23 shapes an ancient functional interplay between ESCRT and ubiquitin system in Asgard archaea

Functional interplay between the endosomal sorting complexes required for transport (ESCRT) and ubiquitin system underlies the ubiquitin-dependent sorting pathway, a specific trait of eukaryotic endomembrane system. Yet, its evolutionary origin remains unclear. Here, we show that a novel UEV-Vps23 family protein, that contains UEV and Vps23 domains, mediates an ancient ESCRT and ubiquitin system interplay in Asgard archaea. The UEV binds ubiquitin with high-affinity, making the UEV-Vps23 a sensor for sorting ubiquitinated cargo. A steadiness box in the Vps23 domain undergoes ubiquitination through a eukaryotic-like Asgard E1, E2, and RING E3 cascade. The UEV-Vps23 can switch between autoinhibited and active forms, by which likely regulates the ESCRT and ubiquitin system interplay. Furthermore, the shared sequence and structural homology among the UEV-Vps23, eukaryotic Vps23 and archaeal CdvA, implying that these proteins share a common evolutionary origin. Together, this work presents evidence that the ESCRT and ubiquitin system interplay had arisen early in Asgard evolution, antedating emergence of endomembrane system in eukaryogenesis. TeaserThe ESCRT and ubiquitin system interplay, a specific trait of eukaryotic endomembrane system, likely inherited from an Asgard archaeal ancestor.

microbiology↗

bioRxiv2023

snoRNA-guided tRNA 2'-O-methylation controls codon-biased gene expression and cellular states

snoRNAs are a large family of noncoding (nc)RNAs present across eukaryotes and archaea. While a subset of them guide 2-O- methylation (Nm) and pseudouridylation ({Psi}) of rRNAs and snRNAs, targets of most snoRNAs remain unknown. Here we used PARIS2 to map snoRNA targets, revealing an extensive and conserved snoRNA-tRNA interaction network. Using optimized denatured RiboMeth-seq (dRMS), we discovered snoRNA-guided Nm sites in ncRNAs, including tRNAs. Loss of snoRNAs and their associated 2-O-methyltransferase FBL reduced tRNA modifications and increased fragmentation. CRISPR knockout of the D97/D133 family of snoRNAs reduced the activity and levels of several target tRNAs, including elongator (e)Met-CAU, leading to codon-biased transcriptome and translatome in human cells. The codon-biased gene expression tipped the balance between the dichotomous cellular states of proliferation and differentiation, and skewed germ layer potential of mouse embryonic stem cells. Together, we discovered a snoRNA-guided tRNA modification mechanism controlling codon-biased gene expression and cellular states.

biochemistry↗

bioRxiv2023

A Connectome of the Male Drosophila Ventral Nerve Cord

Animal behavior is principally expressed through neural control of muscles. Therefore understanding how the brain controls behavior requires mapping neuronal circuits all the way to motor neurons. We have previously established technology to collect large-volume electron microscopy data sets of neural tissue and fully reconstruct the morphology of the neurons and their chemical synaptic connections throughout the volume. Using these tools we generated a dense wiring diagram, or connectome, for a large portion of the Drosophila central brain. However, in most animals, including the fly, the majority of motor neurons are located outside the brain in a neural center closer to the body, i.e. the mammalian spinal cord or insect ventral nerve cord (VNC). In this paper, we extend our effort to map full neural circuits for behavior by generating a connectome of the VNC of a male fly.

neuroscience↗

bioRxiv2023

Fluctuation of lysosomal protein degradation in neural stem cells of postnatal mouse brain

Lysosomes are intracellular organelles responsible for degrading diverse macromolecules delivered from several pathways, such as the endo-lysosomal and autophagic pathways. Recent reports have suggested that lysosomes are essential in regulating neural stem cells in developing, adult, and aged brains. However, the activity of these lysosomes has not yet been monitored in these brain tissues. Here, we report a new probe to measure lysosomal protein degradation in brain tissue by immunostaining. Our results demonstrate the fluctuation of lysosomal protein degradation in neural stem cells depending on age and brain disorder. Neural stem cells increase lysosomal activity during hippocampal development in the dentate gyrus, but aging and aging-related disease reduces their activity. In addition, physical exercise increases lysosomal activity in neural stem cells and astrocytes. We hypothesize three different stages of lysosomal activity: the increase in development, the stable state for the adult stage, and the reduction by damages with age or disease.

neuroscience↗

bioRxiv2023

Single cell transcriptomics of the human parasite Schistosoma mansoni first intra-molluscan stage reveals tentative tegumental and stem cell regulators.

BackgroundSchistosomiasis is a major Neglected Tropical Disease, caused by the infection with blood flukes in the genus Schistosoma. To complete the life cycle, the parasite undergoes asexual and sexual reproduction within an intermediate snail host and a definitive mammalian host, respectively. The intra-molluscan phase provides a critical amplification step that ensures a successful transmission. However, the cellular and molecular mechanisms underlying the development of the intra-molluscan stages remain poorly understood. MethodsS. mansoni mother sporocysts were dissociated into single cell suspensions, and live cells enriched and sequenced using the single cell 10X Genomics Chromium platform. We defined somatic and stem/germinal cell clusters, identified cell type-enriched Gene Ontology (GO) terms, and predicted transcription factor binding sites for key marker genes. ResultsSix cell clusters comprising stem/germinal, two tegument, muscle, neuron, and parenchyma were identified and validated by Fluorescence in situ Hybridisation (FISH). GO term analysis predicted key biological processes for each of the clusters. Using the Self-Assembling Manifold (SAM) algorithm, three sub-clusters were identified within the stem/germinal cell population. Furthermore, transcription factor binding sites and putative transcription factors were predicted for stem/germinal and tegument clusters. ConclusionsWe report a spatially validated single cell transcriptomic analysis of the first intra-molluscan stage of S. mansoni. Key cell regulators were identified, paving the way for future analyses to unveil their role during the parasite development and interaction with its intermediate host.

developmental biology↗

bioRxiv2023

Integrating gene mutation spectra from tumors and the general population with gene expression topological networks to identify novel cancer driver genes

BackgroundUnderstanding the genetics underlying cancer development and progression is the most important goal of biomedical research to improve patient survival rates. Recently, researchers have proposed computationally combining the mutational burden with biological networks as a novel means to identify cancer driver genes. However, these approaches treated all mutations as having the same functional impact on genes and incorporated gene-gene interaction networks without considering tissue specificity, which may have hampered our ability to identify novel cancer drivers. MethodsWe have developed a framework, DGAT-cancer that integrates the predicted pathogenicity of somatic mutation in cancers and germline variants in the healthy population, with topological networks of gene expression in tumor tissues, and the gene expression levels in tumor and paracancerous tissues in predicting cancer drivers. These features were filtered by an unsupervised approach, Laplacian selection, and those selected were combined by Hotelling and Box-Cox transformations to score genes. Finally, the scored genes were subjected to Gibbs sampling to determine the probability that a given gene is a cancer driver. ResultsThis method was applied to nine types of cancer, and achieved the best area under the precision-recall curve compared to three commonly used methods, leading to the identification of 571 novel cancer drivers. One of the top genes, EEF1A1 was experimentally confirmed as a cancer driver of glioma. Knockdown of EEF1A1 led to a ~ 41-50% decrease in glioma size and improved the temozolomide sensitivity of glioma cells. ConclusionBy combining the pathogenic status of mutational spectra in tumors alongside the spectrum of variation in the healthy population, with gene expression in both tumors and paracancerous tissues, DGAT-cancer has significantly improved our ability to detect novel cancer driver genes.

bioinformatics↗

bioRxiv2023

The stage- and sex-specific transcriptome of the human parasite Schistosoma mansoni

The flatworm Schistosoma mansoni is an important but neglected pathogen that causes the disease schistosomiasis in millions of people worldwide. The parasite has a complex life cycle, undergoing sexual reproduction in a mammalian host and asexual replication in a snail host. Understanding the molecular mechanisms the parasite uses to transition between hosts and develop into dimorphic reproductively competent adults may reveal new strategies for control. We present the first comprehensive transcriptomic analysis of S. mansoni, from eggs to juvenile worms. Focusing on eight life stages spanning free-living water-borne and parasitic stages from both intermediate and definitive hosts, we have generated deep RNA-seq data for five replicates per group for a total of 75 data sets. The data were produced using a single approach to increase the accuracy of stage-to-stage comparisons and made accessible via a user-friendly tool to visualise and explore gene expression (https://lifecycle.schisto.xyz/). These data are valuable for understanding the biology and sex-specific development of schistosomes and the interpretation of complementary genomic and functional genetics studies.

molecular biology↗

bioRxiv2023

Dynamic saccade context triggers more stable spatiotopic object-location binding

Our visual systems rapidly perceive and integrate information about object identities and locations. There is long-standing debate about how we achieve world-centered (spatiotopic) object representations across eye movements, with many studies reporting persistent retinotopic (eye-centered) effects even for higher-level object-location binding. But these studies are generally conducted in fairly static experimental contexts. Might spatiotopic object-location binding only emerge in more dynamic saccade contexts? In the present study, we investigated this using the Spatial Congruency Bias paradigm in healthy adults. In the static (single saccade) context, we found purely retinotopic binding, as before. However, robust spatiotopic binding emerged in the dynamic (multiple frequent saccades) context. We further isolated specific factors that modulate retinotopic and spatiotopic binding. Our results provide strong evidence that dynamic saccade context can trigger more stable object-location binding in ecologically-relevant spatiotopic coordinates, perhaps via a more flexible brain state which accommodates improved visual stability in the dynamic world. Significance StatementOne of the most fundamental challenges for human behavior is how we integrate and stabilize perceptual information in our ever-changing sensory environments. In particular, we make multiple eye movements every second, constantly displacing and distorting our visual input. Yet despite receiving visual input in these disjointed, eye-centered (retinotopic) coordinates, we perceive the world as stable, based on objects world-centered (spatiotopic) locations. Our study provides strong evidence for a previously unstudied cue - dynamic saccade context - in triggering more stable object-location binding, which offers a novel step forward in understanding how we form a stable perception of the dynamic world. More broadly, these findings suggest the importance of considering dynamic saccade context in visual perception and cognitive neuroscience studies.

neuroscience↗

bioRxiv2023

Disruption of desmoplastic stroma overcomes restrictions to T cell extravasation, immune exclusion and immunosuppression in solid tumors

The desmoplastic stroma in solid tumors presents a formidable challenge to immunotherapies that rely on endogenous or adoptively transferred T cells, however, the mechanisms are poorly understood. To define mechanisms involved, we treat established desmoplastic pancreatic tumors with CAR T cells directed to fibroblast activation protein (FAP), an enzyme highly overexpressed on a subset of cancer-associated fibroblasts (CAFs). Depletion of FAP+CAFs results in loss of the structural integrity of desmoplastic matrix. This renders these highly treatment-resistant cancers susceptible to subsequent treatment with a tumor antigen (mesothelin)-targeted CAR and to anti-PD1 antibody therapy. Mechanisms include overcoming stroma-dependent restriction of T cell extravasation and/or perivascular invasion, reversing immune exclusion, relieving T cell suppression, and altering the immune landscape by reducing myeloid cell accumulation and increasing endogenous CD8+ T cell and NK cell infiltration. These data provide strong rationale for combining tumor stroma-and malignant cell-targeted therapies to be tested in clinical trials.

immunology↗

bioRxiv2023

Two-fluid dynamics and micron-thin boundary layers shape cytoplasmic flows in early Drosophila embryos

Cytoplasmic flows are widely emerging as key functional players in development. In early Drosophila embryos, flows drive the spreading of nuclei across the embryo. Here, we combine hydrodynamic modeling with quantitative imaging to develop a two-fluid model that features an active actomyosin gel and a passive viscous cytosol. Gel contractility is controlled by the cell cycle oscillator, the two fluids being coupled by friction. In addition to recapitulating experimental flow patterns, our model explains observations that remained elusive, and makes a series of new predictions. First, the model captures the vorticity of cytosolic flows, which highlights deviations from Stokes flow that were observed experimentally but remained unexplained. Second, the model reveals strong differences in the gel and cytosol motion. In particular, a micron-sized boundary layer is predicted close to the cortex, where the gel slides tangentially whilst the cytosolic flow cannot slip. Third, the model unveils a mechanism that stabilizes the spreading of nuclei with respect to perturbations of their initial positions. This self-correcting mechanism is argued to be functionally important for proper nuclear spreading. Fourth, we use our model to analyze the effects of flows on the transport of the morphogen Bicoid, and the establishment of its gradients. Finally, the model predicts that the flow strength should be reduced if the shape of the domain is more round, which is experimentally confirmed in Drosophila mutants. Thus, our two-fluid model explains flows and nuclear positioning in early Drosophila, while making predictions that suggest novel future experiments.

biophysics↗

bioRxiv2023

Viruses in deep-sea cold seep sediments harbor diverse survival mechanisms and remain genetically conserved within species

Deep sea cold seep sediments have been discovered to harbor novel, abundant, and diverse bacterial and archaeal viruses. However, little is known about viral genetic features and evolutionary patterns in these environments. Here, we examined the evolutionary ecology of viruses across active and extinct seep stages in the area of Haima cold seeps in the South China Sea. Diverse antiviral defense systems in 487 microbial genomes spanning 43 families inform the dynamics of host-virus interactions. Accordingly, a total of 338 viral operational taxonomic units are identified and linked to 36 bacterial and archaeal phyla. Cold seep viruses are predicted to harbor diverse adaptive strategies to persist in this environment, including counter-defense systems, reverse transcriptases, auxiliary metabolic genes, and alternative genetic code assignments. Extremely low nucleotide diversity is observed in cold seep viral populations, being influenced by factors including microbial host, sediment depth and cold seep stage. Most cold seep viral genes are under strong purifying selection with trajectories that differ depending on whether cold seeps are active or extinct. This work sheds light on the understanding of environmental adaptation mechanisms and evolutionary patterns of viruses in the sub-seafloor biosphere.

microbiology↗

bioRxiv2023

Multi-omics of the gut microbial ecosystem in the immunotherapy resistance in microsatellite instability-high gastrointestinal cancer patients

Despite the encouraging efficacy of anti-PD-1/PD-L1 immunotherapy in microsatellite instability-high/deficient mismatch repair (MSI-H/dMMR) advanced gastrointestinal cancer, many patients exhibit primary or acquired resistance. Using multi-omics approaches, we interrogated gut microbiome, blood metabolome and cytokines/chemokines of MSI-H/dMMR advanced gastrointestinal cancer patients (N=77) and identified a number of microbes (e.g. Alistipes putredinis) and metabolites (e.g. arginine and SCFA) highly associated with primary resistance. Fecal microbiota transplantation of patients stool replicated the clinical responsiveness as well as certain molecular signatures. Based on the clinical microbiome data, we developed a predictive machine learning model for primary resistance and achieved accuracy at 0.83 on an external validation set. Furthermore, several microbes were pinpointed which gradually changed during the process of acquired resistance. In summary, our study demonstrated the essential role of gut microbiome in drug resistance, and this could be utilized as a preventative diagnosis tool as well as therapeutic targets in the future.

cancer biology↗

bioRxiv2023

Excess PrPC inhibits muscle cell differentiation via miRNA-enhanced liquid-liquid phase separation implicated in myopathy

The cellular prion protein (PrPC), a glycoprotein existing in membrane-bound and cytoplasmic forms, has functional importance in skeletal muscle, but the mechanism behind the phenomenon remains poorly understood. Here we report that PrPC is overexpressed and located in the cytoplasm of the skeletal muscle of six myopathy patients; cytoplasmic PrPC strongly inhibits skeletal muscle cell autophagy and blocks myoblast differentiation. PrPC selectively binds to a subset of miRNAs during myoblast differentiation, and the co-localization of PrPC with miR-214-3p was clearly observed in the skeletal muscle of six myopathy patients but not in that of four age-matched controls. We demonstrate that PrPC is overexpressed in skeletal muscle cells under pathological conditions and inhibits muscle cell differentiation via physically interacting with a subset of miRNAs to significantly inhibit autophagy-related protein 5-dependent autophagy, and selectively recruits these miRNAs into phase-separated condensates in living myoblasts, which in turn greatly enhances liquid-liquid phase separation (LLPS) of PrPC and results in the subsequent PrP aggregation and muscle bundle formation in myopathy patients characterized by incomplete muscle regeneration. Our findings show how excess PrPC can inhibit muscle cell differentiation via miRNA-enhanced LLPS implicated in myopathy.

biochemistry↗

bioRxiv2023

Facial representation comparisons between human brain and deep convolutional neural network reveal a fatigue repetition suppression mechanism

Facial repetition suppression, a well-studied phenomenon characterized by decreased neural responses to repeated faces in visual cortices, remains a subject of ongoing debate regarding its underlying neural mechanisms. Recent advancements have seen deep convolutional neural networks (DCNNs) achieve human-level performance in face recognition. In our present study, we sought to compare brain activation patterns derived from human electroencephalogram (EEG) data with those generated by DCNNs. Employing reverse engineering techniques, we aimed to provide a novel perspective on the neural mechanisms underlying facial repetition suppression. Our approach involved employing brain decoding methods to investigate how representations of faces change with their familiarity in the human brain. Subsequently, we constructed two models for repetition suppression within DCNNs: the Fatigue model, which posits that stronger activation leads to greater suppression, and the Sharpening model, which suggests that weaker activation results in more pronounced suppression. To elucidate the neural mechanisms at play, we conducted cross-modal representational similarity analysis (RSA) comparisons between human EEG signals and DCNN activations. Our results revealed a striking similarity between human brain representations and those of the Fatigue DCNN, favoring the Fatigue model over the Sharpening hypothesis in explaining the facial repetition suppression effect. These representation analyses, bridging the human brain and DCNNs, offer a promising tool for simulating brain activity and making inferences regarding the neural mechanisms underpinning complex human behaviors.

neuroscience↗