Biology subjects

Liu, P.

Publications and source records attributed to Liu, P..

At least 181 records · Page 10Linked to original sources

bioRxiv2023

ERLIN1 may be involved in DHRS1-induced Change in Lipid Droplet Morphology in HeLa Cell

Dehydrogenase/reductase (SDR family) member1, DHRS1, a member of the conserved short chain dehydrogenase/reductase (SDR) superfamily, has been identified in lipid droplets proteome of different cells and tissues. However, until now, little is known about the potential role of DHRS1 on the lipid droplet (LD). Here, we report that DHRS1 localized to the lipid droplet in Huh7 and HeLa cells and ectopic expression of DHRS1 in HeLa cell induced a significant change in the lipid droplet morphology resulting in nearly 2 fold increase both in lipid droplet size and total triacylglycerol level independent of oleic acid treatment. DHRS1 interacted with ERLIN1, a non-caveolae lipid raft-like domain marker, in HeLa cell and ERLIN1 deficient HeLa cells displayed no detectable change in LD morphology. Although ectopic expression of DHRS1-GFP fusion protein in ERLIN1 deficient HeLa cells resulted in fewer GFP-labeled ring structures relative to WT HeLa cell; thus suggesting that ERLIN1 may be involved in regulating DHRS1 protein turnover. Taken together, these data showed that DHRS1 localized to the LD and induced a significant change in LD morphology which may be regulated by ERLIN1.

cell biology↗

bioRxiv2023

A layer-specific model of cortical sensory aging

The segregation of processes into cortical layers is a convergent feature in animal evolution. However, how changes in the cortical layer architecture interact with sensory system function and dysfunction remains unclear. We conducted functional and structural layer-specific in-vivo 7T-MRI of the primary somatosensory cortex in two cohorts of healthy younger and older adults. Input layer IV is enlarged and more myelinated in older adults, and associated with extended sensory input signals. Age-related cortical thinning is driven by deep layers and accompanied by increased myelination, but there is no clear evidence for reduced inhibition. Calcium imaging and histology in younger and older mice reveal increased sensory-evoked neuronal activity accompanied by increased parvalbumin expression as a potential inhibitory balance, with dynamic changes in layer-specific myelination across age groups. Using multimodal imaging, we demonstrate that middle and deep layers show specific sensitivity to aging across species.

neuroscience↗

bioRxiv2023

Multifrequency control of Faraday wave bioassembly for constructing multiscale hPSC-derived neuronal networks

Bioassembly is recently regarded as a critical alternative biofabrication technical route to bioprinting since it can directly manipulate millions of live cells to form multicellular structures with close intercellular proximity, improving contact-dependent cell communication and promoting the emergence of tissue-specific functions. However, acoustic bioassembly techniques are currently limited to generating cytoarchitecture with a single characteristic length which cannot faithfully mimic the multiscale cellular structures in native tissues. To overcome this challenge, herein we report a novel acoustic bioassembly technique that employs multifrequency control of Faraday waves to form multiscale cellular structures. By superimposing multiple sine wave signals with proper amplitude ratios, Faraday waves containing multiple wavelengths can be induced and enabled to generate multiscale structures in few seconds. Using this technique, we construct functional neuronal networks with multiscale connectivity that display spontaneous neuroelectrical activities. We anticipate this technique will find wide applications in tissue engineering and regenerative medicine.

bioengineering↗

bioRxiv2023

UPRER-immunity axis acts as physiological food evaluation system that promotes aversion behavior in sensing low-quality food

To survive in challenging environments, animals must develop a system to assess food quality and adjust their feeding behavior accordingly. However, the mechanisms that regulate this chronic physiological food evaluation system, which monitors specific nutrients from ingested food and influences food-response behavior, are still not fully understood. Here, we established a low-quality food evaluation assay system and found that heat-killed E. coli (HK-E. coli), a low sugar food, triggers cellular UPRER and immune response. This encourages animals to avoid low-quality food. The physiological system for evaluating low-quality food depends on the UPRER (IRE-1/XBP-1) - Innate immunity (PMK-1/p38 MAPK) axis, particularly its neuronal function, which subsequently regulates feeding behaviors. Moreover, animals can adapt to a low-quality food environment through sugar supplementation, which inhibits the UPRER -PMK-1 regulated stress response by increasing vitamin C biosynthesis. This study reveals the role of the cellular stress response pathway as physiological food evaluation system for assessing nutritional deficiencies in food, thereby enhancing survival in natural environments.

developmental biology↗

bioRxiv2023

MiRGraph: A transformer-based feature learning approach to identify miRNA-target interactions

MicroRNAs (miRNAs) mediates gene expression regulation by targeting specific messenger RNAs (mRNAs) in the cytoplasm. They can function as both tumor suppressors and oncogenes depending on the specific miRNA and its target genes. Detecting miRNA-target interactions (MTIs) is critical for unraveling the complex mechanisms of gene regulation and promising towards RNA therapy for cancer. There is currently a lack of MTIs prediction methods that simultaneously perform feature learning from heterogeneous gene regulatory network (GRN) and genomic sequences. To improve the prediction performance of MTIs, we present a novel transformer-based multiview feature learning method - MiRGraph, which consists of two main modules for learning the sequence-based and GRN-based feature embedding. For the former, we utilize the mature miRNA sequences and the complete 3UTR sequence of the target mRNAs to encode sequence features using a hybrid transformer and convolutional neural network (CNN) (TransCNN) architecture. For the latter, we utilize a heterogeneous graph transformer (HGT) module to extract the relational and structural information from the GRN consisting of miRNA-miRNA, gene-gene and miRNA-target interactions. The TransCNN and HGT modules can be learned end-to-end to predict experimentally validated MTIs from MiRTarBase. MiRGraph outperforms existing methods in not only recapitulating the true MTIs but also in predicting strength of the MTIs based on the in-vitro measurements of miRNA transfections. In a case study on breast cancer, we identified plausible target genes of an oncomir.

bioinformatics↗

bioRxiv2023

Atlas of Fshr Expression from Novel Reporter Mice

The FSH-FSHR signaling pathway has traditionally been considered an essential regulator in reproductive development and fertility. But there has been emerging evidence of FSHR expression in extragonadal tissues/organs. This poses new questions and long-term debates regarding the physiological role of the FSH-FSHR pathway, and underscores the need for reliable, in vivo analysis of FSHR expression in animal models. However, conventional methods have proven insufficient for examining FSHR expression due to limitations, such as the scarcity of reliable antibodies, rapid turnover/degradation of transcripts, and a lack of robust in vivo tools. To address this challenge, we developed Fshr-ZsGreen knockin reporter mice under the control of Fshr endogenous promoter using CRISPR/Cas9 genome-editing technology to append a P2A-ZsGreen targeting vector into a locus between the last exon and the stop codon of Fshr. With this novel genetic tool, we provide a reliable readout of Fshr expression at single-cell resolution level in vivo and in real time. Reporter animals were also subjected to additional analyses, including immunohistochemical staining, ddRT-PCR, and in situ hybridization, to define the accurate expression profile of FSHR in gonadal and extragonadal organs/tissues. Our compelling results not only demonstrated Fshr expression in intragonadal tissues but also, strikingly, unveiled notably increased expression in Leydig cells, osteoblast lineage cells, endothelial cells in vascular structures, and epithelial cells in bronchi of the lung and renal tubes. The genetic decoding of the widespread pattern of Fshr expression highlights its physiological relevance beyond reproduction and fertility, and opens new avenues for therapeutic options for age-related disorders of the bones, lungs, kidneys, and hearts, among other tissues/organs. Exploiting the power of the Fshr knockin reporter animals, this report provides the first comprehensive genetic record of the spatial distribution of FSHR expression, correcting a long-term misconception about Fshr expression and offering prospects for extensive exploration of FSH-FSHR biology.

cell biology↗

bioRxiv2023

Spatiotemporal Profiling Unveiling the Cellular Organization Patterns and Local Protumoral Immune Microenvironment Remodeling in Early Lung Adenocarcinoma Progression

Spatial cellular organization patterns (COPs) in tumor microenvironment influence the tumor progression and therapeutic response, however, little is known about the cellular composition and functional potential of these multicellular structures during lung adenocarcinoma progression. Here, we integrate spatial transcriptomics with single cell RNA sequencing to characterize the local tumor and immunological landscape of samples from 8 patients with early-stage lung adenocarcinoma at different pathological stages. We identified ten COPs that show distinct associations with local immune states and clinical outcomes, including survival and therapy response. The local infiltration levels of regulatory and dysfunctional immune cells are increased with pathological progression. Cell-to-cell interactions between malignant cells and tumor microenvironment (TME) cells were involved in protumor immune state remodeling. Finally, we detected a group of malignant cells that were specifically located at the tumor boundary, representing a more aggressive state, were involved in the invasion of invasive adenocarcinoma (IAC). Altogether, these results can improve our understanding of the local microenvironment characteristics that underlie LUAD progression and may facilitate the identification of drug targets to prevent invasive progression and biomarkers for diagnosis.

cell biology↗

bioRxiv2023

M1 Macrophage-Related Genes Model for NSCLC Immunotherapy Response Prediction

2.Patients diagnosed with non-small cell lung cancer have a limited lifespan and exhibit poor immunotherapy outcomes. M1 macrophages have been found to be essential for anti-tumor immunity. This study aimed to develop an immunotherapy response evaluation model for NSCLC patients based on transcriptional expression. RNA sequencing profiles of 254 advanced-stage NSCLC patients treated with immunotherapy were downloaded from POPLAR and OAK projects. Immune cell infiltration in NSCLC patients has been examined, and thereafter different co-expressed genes were identified. Following that, the impact of M1 macrophage related genes on the prognosis of NSCLC patients was investigated. Six M1 macrophage co-expression genes, namely NKX2-1, CD8A, SFTA3, IL2RB, IDO1, and CXCL9, exhibited a strong association with the prognosis of NSCLC and served as effective predictors for immunotherapy response. A response model was constructed using Cox regression model and Lasso Cox regression analysis. The M1 genes were validated on our previous TD- FOREKNOW NSCLC clinical trial by RT-qPCR. The response model showed excellent immunotherapy response predicting and prognosis evaluating value in advanced stage of NSCLC. The model can effectively predict advanced NSCLC prognosis and aid in identifying patients who could benefit from customized immunotherapy as well as sensitive drugs.

immunology↗

bioRxiv2023

Addressing the dNTP bottleneck restricting prime editing activity

Prime editing efficiency is modest in cells that are quiescent or slowly proliferating where intracellular dNTP levels are tightly regulated. MMLV-reverse transcriptase - the prime editor polymerase subunit - requires high intracellular dNTPs levels for efficient polymerization. We report that prime editing efficiency in primary cells and in vivo is increased by mutations that enhance the enzymatic properties of MMLV-reverse transcriptase and can be further complemented by targeting SAMHD1 for degradation.

biochemistry↗

bioRxiv2023

Ptth regulates lifespan through innate immunity pathway in Drosophila

The prothoracicotropic hormone (PTTH) is a well-known neuropeptide that regulates insect metamorphosis (the juvenile-to-adult transition) by inducing the biosynthesis of steroid hormones. However, the role of PTTH in adult physiology and longevity is largely unexplored. Here, we show that Ptth loss-of-function mutants are long-lived and exhibit increased resistance to oxidative stress in Drosophila. Intriguingly, we find that loss of Ptth blunt age-dependent upregulation of NF-{kappa}B signaling specifically in fly hepatocytes (oenocytes). We further show that oenocyte-specific overexpression of Relish/NF-{kappa}B blocks the lifespan extension of Ptth mutants, suggesting that PTTH regulates lifespan through oenocyte-specific NF-{kappa}B signaling. Surprisingly, adult-specific knockdown of Ptth did not prolong lifespan, indicating that PTTH controls longevity through developmental programs. Indeed, knockdown of PTTH receptor Torso in prothoracic gland (PG) during fly development prolongs lifespan. To uncover the developmental processes underlying PTTH-regulated lifespan, we perform a developmental transcriptomic analysis and identify an unexpected activation of NF-{kappa}B signaling in developing oenocytes during fly metamorphosis, which is blocked in Ptth mutants. Importantly, knockdown of Relish/NF-{kappa}B specifically in oenocytes during early pupal stages significantly prolongs the lifespan of adult flies. Thus, our findings uncover an unexpected role of PTTH in controlling adult lifespan through temporal and spatial activation of NF-{kappa}B signaling in developing hepatocytes and highlight the vital role of developmental NF-{kappa}B signaling in shaping adult physiology. Significance StatementDespite the strong link between animal development and adult lifespan, we know little about how developmental programs impact adult longevity, and when and where such programs are activated during development. Here, we demonstrate that loss of insect hormone PTTH prolongs lifespan and healthspan by repressing chronic inflammation in Drosophila. Intriguingly, we demonstrate that PTTH regulates adult lifespan through temporal and spatial activation of NF-{kappa}B signaling in developing hepatocytes during insect metamorphosis. These findings provide novel insights into the developmental programs that impact adult longevity.

physiology↗

bioRxiv2023

A redundant chloroplast protein is co-opted by potyvirids as the scaffold protein to mediate viral intercellular movement complex assembly

For viruses in the family Potyviridae (potyvirids), three virus-encoded proteins (P3N-PIPO, CI and CP) and several host components are known to coordinately regulate viral cell-to-cell movement. Here, we found that HCPro2 encoded by areca palm necrotic ring spot virus is involved in the intercellular movement, which could be functionally complemented by its counterpart HCPro from a potyvirus. The affinity purification and mass spectrum analysis identified several viral factors (including CI and CP) and a variety of host proteins that physically associate with HCPro2. We demonstrated that HCPro2 interacts with either CI or CP in planta, and the three form plasmodesmata (PD)-localized interactive complex in viral infection. Further, we screened HCPro2-associating host proteins, and identified a common host protein RbCS that mediates the interactions of HCPro2-CI, HCPro2-CP and CI-CP among the complex. Knockdown of NbRbCS simultaneously impairs the interactions of HCPro2-CI, HCPro2-CP and CI-CP, and significantly attenuates the intercellular movement and systemic infection for ANRSV and other three tested potyvirids. This study highlights that a nucleus-encoded chloroplast-targeted protein is hijacked by potyvirids as the scaffold protein to mediate the assembly of viral intercellular movement complex to promote viral infection.

microbiology↗

bioRxiv2023

Analyzing the link between RNA secondary structures and R-loop formation with tree polynomials

R-loops are a class of non-canonical nucleic acid structures that typically form during transcription when the nascent RNA hybridizes the DNA template strand, leaving the DNA coding strand unpaired. Co-transcriptional R-loops are abundant in nature and biologically relevant. Recent research shows that DNA sequence and topology affect R-loops, yet it remains unclear how these and other factors drive R-loop formation. In this work, we investigate a link between the secondary structure of the nascent RNA and the probability of R-loop formation. We introduce tree-polynomial representations, a class of mathematical objects that enable accurate and efficient data analysis of RNA secondary structures. With tree-polynomials, we establish a strong correlation between the secondary structure of the RNA transcript and the probability of R-loop formation. We identify that branches with short stems separated by multiple bubbles in the RNA secondary structure are associated with the strong correlation and are predictive of R-loop formation.

molecular biology↗

bioRxiv2023

Evaluating and Improving Health Equity and Fairness of Polygenic Scores

Polygenic scores (PGS) are quantitative metrics for predicting phenotypic values, such as human height or disease status. Some PGS methods require only summary statistics of a relevant genome-wide association study (GWAS) for their score. One such method is Lassosum, which inherits the model selection advantages of Lasso to select a meaningful subset of the GWAS single nucleotide polymorphisms as predictors from their association statistics. However, even efficient scores like Lassosum, when derived from European-based GWAS, are poor predictors of phenotype for subjects of non-European ancestry; that is, they have limited portability to other ancestries. To increase the portability of Lassosum, when GWAS information and estimates of linkage disequilibrium are available for both ancestries, we propose Joint-Lassosum. In the simulation settings we explore, Joint-Lassosum provides more accurate PGS compared with other methods, especially when measured in terms of fairness. Like all PGS methods, Joint-Lassosum requires selection of predictors, which are determined by data-driven tuning parameters. We describe a new approach to selecting tuning parameters and note its relevance for model selection for any PGS. We also draw connections to the literature on algorithmic fairness and discuss how Joint-Lassosum can help mitigate fairness-related harms that might result from the use of PGS scores in clinical settings. While no PGS method is likely to be universally portable, due to the diversity of human populations and unequal information content of GWAS for different ancestries, Joint-Lassosum is an effective approach for enhancing portability and reducing predictive bias.

genetics↗

bioRxiv2023

A brown fat-enriched adipokine, ASRA, is a leptin receptor antagonist that stimulates appetite

The endocrine control of food intake remains incompletely understood, and whether the leptin receptor (LepR)-mediated anorexigenic pathway in the hypothalamus is negatively regulated by a humoral factor is unknown. Here, we identify an appetite-stimulating factor - ASRA - that represents a peripheral signal of energy deficit and orthosterically antagonizes LepR signaling. Asra encodes an 8 kD protein that is abundantly and selectively expressed in adipose tissue and to a lesser extent, in liver. ASRA associates with autophagy vesicles and its secretion is enhanced by energy deficiency. In vivo, fasting and cold stimulate Asra expression and increase its protein concentration in cerebrospinal fluid. Asra overexpression attenuates LepR signaling, leading to elevated blood glucose and development of severe hyperphagic obesity. Conversely, either adipose- or liver-specific Asra knockout mice display increased leptin sensitivity, improved glucose homeostasis, reduced food intake, resistance to high-fat diet-induced obesity, and blunted cold-evoked feeding response. Mechanistically, ASRA acts as a high affinity antagonist of LepR. AlphaFold2-multimer prediction and mutational studies suggest that a core segment of ASRA binds to the immunoglobin-like domain of LepR, similar to the site 3 recognition of the A-B loop of leptin. While administration of recombinant wild-type ASRA protein promotes food intake and increases blood glucose in a LepR signaling-dependent manner, point mutation within ASRA that disrupts LepR-binding results in a loss of these effects. Our studies reveal a previously unknown endocrine mechanism in appetite regulation and have important implications for our understanding of leptin resistance.

molecular biology↗

bioRxiv2023

Elasticity of adhesion bonds determines multistable mechanosensitive behaviour of living cells.

The ability of cells to sense the mechanical properties of their microenvironment is essential to many physiological processes. The molecular clutch theory has played an important role in explaining many mechanosensitive cell behaviors. However, its current implementations have limited ability to understand how molecular heterogeneity, such as adhesion molecules with different elasticities, regulates the mechanical response of cell adhesion. In this study, we developed a model incorporating the experimentally measured elastic properties of such proteins to investigate their influence on cell adhesion. It was found that the model not only could accurately fit previous experimental measurements of cell traction force and retrograde actin flow, but also predicted multistablility of cell adhesion as well as a feedback loop between the densities of the extracellular matrix proteins and contractile myosin II motors in living cells. The existence of such a feedback loop was successfully confirmed in experiments. Taken together, our study provides a theoretical framework for understanding how the mechanical properties of adaptor proteins, local substrate deformations and myosin II contractility affect cell adhesion across different cell types and physiological conditions.

biophysics↗

bioRxiv2023

Transcriptional suppression of sphingolipid catabolism controls pathogen resistance in C. elegans

Sphingolipids are required for diverse biological functions and are degraded by specific catabolic enzymes. However, the mechanisms that regulate sphingolipid catabolism are not known. Here we characterize a transcriptional axis that regulates sphingolipid breakdown to control resistance against bacterial infection. From an RNAi screen for transcriptional regulators of pathogen resistance in the nematode C. elegans, we identified the nuclear hormone receptor nhr-66, a ligand-gated transcription factor homologous to human hepatocyte nuclear factor 4. Tandem chromatin immunoprecipitation-sequencing and RNA sequencing experiments revealed that NHR-66 is a transcriptional repressor, which directly targets sphingolipid catabolism genes. Transcriptional de-repression of two sphingolipid catabolic enzymes in nhr-66 loss-of-function mutants drives the breakdown of sphingolipids, which enhances host susceptibility to infection with the bacterial pathogen Pseudomonas aeruginosa. These data define transcriptional control of sphingolipid catabolism in the regulation of cellular sphingolipids, a process that is necessary for pathogen resistance.

immunology↗

bioRxiv2023

Human receptive endometrial organoid for deciphering the implantation window

Human endometrial receptivity is a critical determinant of pregnancy success; however, in vivo studies of its features and regulation are particularly challenging due to ethical restriction. Recently, the development of human endometrial assembloids has provided a powerful model to investigate this intricate biological process. In this study, we established a specialized human window-of-implantation (WOI) endometrial assembloid system that mimics the in vivo receptive endometrium. It not only reproduces the structural attributes of pinopodes and cilia, but also molecular characteristics of mid-secretory endometrium. Furthermore, the WOI endometrial assembloid exhibits hormone responsiveness, an energy metabolism profile characterized by larger and functionally enhanced mitochondria, increased ciliary assembly and motility, and epithelial-mesenchymal transition (EMT), as well as promising potential for embryo implantation. As such, WOI assembloids hold great promise as a platform to unravel the intricate mechanisms governing the regulation of endometrial receptivity, maternal-fetal interactions, and associated pathologies, ultimately driving impactful advancements in the field.

cell biology↗

bioRxiv2023

Discovery of fibrotic intervertebral disc in mice

Intervertebral discs are crucial to spine flexibility and stability during locomotion, but the mechanism of their mechanoadaptation to stress remains inadequately elucidated. We discovered spontaneous collagenesis in discs at the tail base in mice occurring from 14 days post-natal development. These discs termed as type C, differ from typical discs by exhibiting intensive collagen II and reduced aggrecan deposition contributing to the stiffening of the extracellular matrix (ECM), without typical degenerative markers. The reinforced mechanical properties enable type C discs to withstand high mechanical stress during flexion. Further analysis revealed that type C discs experience a turnover in cell composition, with the emergence of Procr+ progenitor cells and depletion of notochord cells. We demonstrated the essential role of mechanical stress in type C disc formation, suggesting a mechanoadaptive process rather than a pathological condition. Mechanistically, we identified TRPV4, as pivotal factors in collagen II synthesis in type C discs, highlighting the role of mechanotransduction in this adaptation. Our findings introduce a novel mechanoadaptive process of intervertebral disc by orchestrating collagenesis, advancing understanding of diverse disc functions in spine development and homeostasis, thereby providing insights for leveraging this mechanism to address spinal disorders.

pathology↗