Biology subjects

Wen, Y.

Publications and source records attributed to Wen, Y..

At least 55 records · Page 3Linked to original sources

bioRxiv2024

High-throughput diversification of protein-ligand surfaces to discover chemical inducers of proximity

Chemical inducers of proximity (CIPs) stabilize biomolecular interactions, often causing an emergent rewiring of cellular biochemistry1,2. While rational design strategies can expedite the discovery of heterobifunctional CIPs, monovalent, molecular glue-like CIPs have relied predominantly on serendipity3. Envisioning a prospective approach to discover molecular glues for a pre-selected target, we hypothesized that pre-existing ligands could be systematically decorated with chemical modifications to empirically discover protein-ligand surfaces that are tuned to cooperatively engage another protein interface. Here, we used sulfur(VI)-fluoride exchange (SuFEx)-based high-throughput chemistry (HTC) to install 3,163 structurally diverse chemical building blocks onto ENL and BRD4 ligands and then screened the crude products for degrader activity. This revealed dHTC1, a potent, selective, and stereochemistry-dependent degrader of ENL. It recruits CRL4CRBN to ENL through an extended interface of protein-protein and protein-ligand contacts, but only after pre-forming the ENL:dHTC1 complex. We also characterized two structurally distinct BRD4 degraders, including dHTC3, a molecular glue that selectively dimerizes the first bromodomain of BRD4 to SCFFBXO3, an E3 ligase not previously accessible for chemical rewiring. Altogether, this study introduces HTC as a facile tool to discover new CIPs and actionable cellular effectors of proximity pharmacology.

biochemistry↗

bioRxiv2024

GenoM7GNet: An Efficient N7-methylguanosine Site Prediction Approach Based on a Nucleotide Language Model

N7-methylguanosine (m7G), one of the mainstream post-transcriptional RNA modifications, occupies an exceedingly significant place in medical treatments. However, classic approaches for identifying m7G sites are costly both in time and equipment. Meanwhile, the existing machine learning methods extract limited hidden information from RNA sequences, thus making it difficult to improve the accuracy. Therefore, we put forward to a deep learning network, called "GenoM7GNet," for m7G site identification. This model utilizes a Bidirectional Encoder Representation from Transformers (BERT) and is pretrained on nucleotide sequences data to capture hidden patterns from RNA sequences for m7G site prediction. Moreover, through detailed comparative experiments with various deep learning models, we discovered that the one-dimensional convolutional neural network (CNN) exhibits outstanding performance in sequence feature learning and classification. The proposed GenoM7GNet model achieved 0.953 in accuracy, 0.932 in sensitivity, 0.976 in specificity, 0.907 in Matthews Correlation Coefficient and 0.984 in Area Under the receiver operating characteristic Curve on performance evaluation. Extensive experimental results further prove that our GenoM7GNet model markedly surpasses other state-of-the-art models in predicting m7G sites, exhibiting high computing performance.

bioinformatics↗

bioRxiv2024

Sex specific knee joint soft tissue mineralization with Fibrillin-1 mutation in male Tight Skin mice.

Articular soft tissue mineralization and ossification are clear pathological signs of osteoarthritis joints. However their molecular and cellular aetiologies remain largely unknown. TGF-{beta} family members are known contributors to both pathological ossification and osteoarthritis development. In this study, we used a Fibrillin-1 mutant mouse, the Tight Skin mouse (TSK), to define the detrimental effects of abnormal Fbn1 in TSK mice and known high TGF-{beta} activity in joint pathology such as articular soft tissue mineralization and ossification. Knee joints of male and Female TSK and Wild-type (WT) littermates were analysed my micro-CT imaging and histology for articular soft tissue pathologies, as well as OA severity. Both aged (10, 26, 35 and 52wks) and following in vivo non-invasive repetitive joint overloading were used. We find that male TSK mice develop spontaneous soft tissue ossification from 26wks of age, followed by increased osteoarthritis at 1 year-old. In addition, knee joint overloading induced ligament and meniscal mineralisation and ossification in both WT and TSK male mice, but were significantly more severe in TSK knees, including ossification of the patella ligament and synovial lining. In contrast, female TSK knees did not develop more severe soft tissue mineralisation compared to littermate WT mice in neither aged nor overloaded knees. We conclude that Fbn1 mutation, and possibly overactive TGF-{beta} activity in TSK mice, induce articular soft tissue ossification and osteoarthritis in a sex-specific manner. Further studies are needed to confirm the specific signalling involved and the relative protection from female mice from such pathologies.

pathology↗

bioRxiv2024

microRNA-1 Regulates Metabolic Flexibility in Skeletal Muscle via Pyruvate Metabolism

MicroRNA-1 (miR-1) is the most abundant miRNA in adult skeletal muscle. To determine the function of miR-1 in adult skeletal muscle, we generated an inducible, skeletal muscle-specific miR-1 knockout (KO) mouse. Integration of RNA-sequencing (RNA-seq) data from miR-1 KO muscle with Argonaute 2 enhanced crosslinking and immunoprecipitation sequencing (AGO2 eCLIP-seq) from human skeletal muscle identified miR-1 target genes involved with glycolysis and pyruvate metabolism. The loss of miR-1 in skeletal muscle induced cancer-like metabolic reprogramming, as shown by higher pyruvate kinase muscle isozyme M2 (PKM2) protein levels, which promoted glycolysis. Comprehensive bioenergetic and metabolic phenotyping combined with skeletal muscle proteomics and metabolomics further demonstrated that miR-1 KO induced metabolic inflexibility as a result of pyruvate oxidation resistance. While the genetic loss of miR-1 reduced endurance exercise performance in mice and in C. elegans, the physiological down-regulation of miR-1 expression in response to a hypertrophic stimulus in both humans and mice causes a similar metabolic reprogramming that supports muscle cell growth. Taken together, these data identify a novel post-translational mechanism of adult skeletal muscle metabolism regulation mediated by miR-1.

physiology↗

bioRxiv2024

Computing hematopoiesis plasticity in response to genetic mutations and environmental stimulations

Cell plasticity (CP), describing a dynamic cell state, plays a crucial role in maintaining homeostasis during organ morphogenesis, regeneration and damage-to-repair biological process. Single-cell-omics datasets provide unprecedented resource to empowers analysis on CP. Hematopoiesis offers fertile opportunities to develop quantitative methods for understanding CP with rich supports from experimental ground-truths. In this study we generated high-quality lineage-negative (Lin-) single-cell RNA-sequencing datasets under various conditions and introduced a working pipeline named Snapdragon to interrogate naive and disturbed plasticity of hematopoietic stem and progenitor cells (HSPCs) with mutational or environmental challenges. Utilizing embedding methods UMAP or FA, a continuum of hematopoietic development is visually observed in wildtype where the pipeline confirms a very low Proportion of hybrid-cells (Phc, with bias range: 0.4-0.6) on a transition trajectory. Upon Tet2 mutation, a driver of leukemia, or treatment of DSS, an inducer of colitis, Phc is increased and plasticity of HSPCs was enhanced. Quantitative analysis indicates that Tet2 mutation enhances HSC self-renewal capability while DSS treatment results in an enhanced myeloid-skewing trajectory, suggesting their similar but different consequences. We prioritized several transcription factors (i.e the EGR family) and signaling pathways (i.e. receptors IL1R1 and ADRB, inflammation and sympathy-sensing respectively) which are responsible for Phc alterations. CellOracle-based simulation suggests that knocking-out EGR regulons or pathways of IL1R1 and ADRB partially reverses Phc promoted by Tet2 mutation and inflammation. In conclusion, the study provides high-quality datasets with single-cell transcriptomic matrices for diversified hematopoietic simulations and a computational pipeline Snapdragon for quantifying disturbed Phc and CP. (247 words) HighlightsO_LITo guide CP analysis, we introduce a quantizable parameter Phc and a pipeline Snapdragon, which discriminate naive and disturbed hematopoiesis; C_LIO_LIThe Snapdragon pipeline analysis on Tet2+/-Lin- cells demonstrates many novel insights, including enhanced HSC plasticity and increased PHC; similar trends are observed in inflammatory Lin- cells; C_LIO_LIRegulon analysis suggests that transcriptional factor EGR1 is significantly activated to elevated the HSC plasticity and change hematopoietic trajectory; C_LIO_LIStress-response-related signaling pathways mediated by receptors IL1R1 or ADRB were obviously activated in the challenged hematopoiesis; C_LIO_LICellOracle-based simulation suggests that knocking-out EGR regulons or pathways of IL1R1 and ADRB partially reverses Phc promoted by Tet2 mutation and inflammation. C_LI

developmental biology↗

bioRxiv2024

PerturbAtlas: A Comprehensive Atlas of Public Genetic Perturbation Bulk RNA-seq Datasets

Manipulating gene expression is crucial for understanding gene function, with high-throughput sequencing techniques such as RNA-seq elucidating the downstream mechanisms involved. However, the lack of a standardized metadata format for small-scale perturbation expression datasets in public repositories hinders their reuse. To address this issue, we developed PerturbAtlas, an add-value resource that re-analyzes publicly archived RNA-seq libraries to provide quantitative data on gene expression, transcript profiles, and alternative splicing events following genetic perturbation. PerturbAtlas assists users in identifying trends at the gene and isoform levels in perturbation assays by re-analyzing a curated set of 122,801 RNA-seq libraries across 13 species. This resource is freely available at https://perturbatlas.kratoss.site as both raw data tables and an interactive browser, allowing searches by species, tissue, or genomic features. The results provide detailed information on alterations following perturbations, accessible through both forward and reverse approaches, thereby enabling the exploration of perturbation consequences and the identification of potential causal perturbations. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=199 SRC="FIGDIR/small/605482v1_ufig1.gif" ALT="Figure 1"> View larger version (76K): org.highwire.dtl.DTLVardef@150012org.highwire.dtl.DTLVardef@b7ac25org.highwire.dtl.DTLVardef@86c4feorg.highwire.dtl.DTLVardef@1ef3341_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioinformatics↗

bioRxiv2024

Microbial-Derived Exerkines Prevent Skeletal Muscle Atrophy

Regular exercise yields a multitude of systemic benefits, many of which may be mediated through the gut microbiome. Here, we report that cecal microbial transplants (CMTs) from exercise-trained vs. sedentary mice have modest benefits in reducing skeletal muscle atrophy using a mouse model of unilaterally hindlimb-immobilization. Direct administration of top microbial-derived exerkines from an exercise-trained gut microbiome preserved muscle function and prevented skeletal muscle atrophy.

physiology↗

bioRxiv2024

CTCF mutation at R567 causes developmental disorders via 3D genome rearrangement and abnormal neurodevelopment

The three-dimensional genome structure organized by CTCF is required for development. Clinically identified mutations in CTCF have been linked to adverse developmental outcomes. Nevertheless, the underlying mechanism remains elusive. In this investigation, we explored the regulatory roles of a clinically relevant R567W point mutation, located within the 11th zinc finger of CTCF, by introducing this mutation into both murine models and human embryonic stem cell-derived cortical organoid models. Mice with homozygous CTCFR567W mutation exhibited growth impediments, resulting in postnatal mortality, and deviations in brain, heart, and lung development at the pathological and single- cell transcriptome levels. This mutation induced premature stem-like cell exhaustion, accelerated the maturation of GABAergic neurons, and disrupted neurodevelopmental and synaptic pathways. Additionally, it specifically hindered CTCF binding to peripheral motifs upstream to the core consensus site, causing alterations in local chromatin structure and gene expression, particularly at the clustered protocadherin locus. Comparative analysis using human cortical organoids mirrored the consequences induced by this mutation. In summary, this study elucidates the influence of the CTCFR567W mutation on human neurodevelopmental disorders, paving the way for potential therapeutic interventions.

molecular biology↗

bioRxiv2024

The 24-Hour Time Course of Integrated Molecular Responses to Resistance Exercise in Human Skeletal Muscle Implicates MYC as a Hypertrophic Regulator That is Sufficient for Growth

Molecular control of recovery after exercise in muscle is temporally dynamic. A time course of biopsies around resistance exercise (RE) combined with -omics is necessary to better comprehend the molecular contributions of skeletal muscle adaptation in humans. Vastus lateralis biopsies before and 30 minutes, 3-, 8-, and 24-hours after acute RE were collected. A time-point matched biopsy-only group was also included. RNA-sequencing defined the transcriptome while DNA methylomics and computational approaches complemented these data. The post-RE time course revealed: 1) DNA methylome responses at 30 minutes corresponded to upregulated genes at 3 hours, 2) a burst of translation- and transcription-initiation factor-coding transcripts occurred between 3 and 8 hours, 3) global gene expression peaked at 8 hours, 4) ribosome-related genes dominated the mRNA landscape between 8 and 24 hours, 5) methylation-regulated MYC was a highly influential transcription factor throughout the 24-hour recovery and played a primary role in ribosome-related mRNA levels between 8 and 24 hours. The influence of MYC in human muscle adaptation was strengthened by transcriptome information from acute MYC overexpression in mouse muscle. To test whether MYC was sufficient for hypertrophy, we generated a muscle fiber-specific doxycycline inducible model of pulsatile MYC induction. Periodic 48-hour pulses of MYC over 4 weeks resulted in higher muscle mass and fiber size in the soleus of adult female mice. Collectively, we present a temporally resolved resource for understanding molecular adaptations to RE in muscle and reveal MYC as a regulator of RE-induced mRNA levels and hypertrophy.

cell biology↗

bioRxiv2024

The Ubiquitin Ligase RBX2/SAG Regulates Mitochondrial Ubiquitination and Mitophagy

Clearance of damaged mitochondria via mitophagy is crucial for cellular homeostasis. While the role of ubiquitin (Ub) ligase PARKIN in mitophagy has been extensively studied, increasing evidence suggests the existence of PARKIN-independent mitophagy in highly metabolically active organs such as the heart. Here, we identify a crucial role for Cullin-RING Ub ligase 5 (CRL5) in basal mitochondrial turnover in cardiomyocytes. CRL5 is a multi-subunit Ub ligase comprised by the catalytic RING box protein RBX2 (also known as SAG), scaffold protein Cullin 5 (CUL5), and a substrate-recognizing receptor. Analysis of the mitochondrial outer membrane-interacting proteome uncovered a robust association of CRLs with mitochondria. Subcellular fractionation, immunostaining, and immunogold electron microscopy established that RBX2 and Cul5, two core components of CRL5, localizes to mitochondria. Depletion of RBX2 inhibited mitochondrial ubiquitination and turnover, impaired mitochondrial membrane potential and respiration, and increased cell death in cardiomyocytes. In vivo, deletion of the Rbx2 gene in adult mouse hearts suppressed mitophagic activity, provoked accumulation of damaged mitochondria in the myocardium, and disrupted myocardial metabolism, leading to rapid development of dilated cardiomyopathy and heart failure. Similarly, ablation of RBX2 in the developing heart resulted in dilated cardiomyopathy and heart failure. Notably, the action of RBX2 in mitochondria is not dependent on PARKIN, and PARKIN gene deletion had no impact on the onset and progression of cardiomyopathy in RBX2-deficient hearts. Furthermore, RBX2 controls the stability of PINK1 in mitochondria. Proteomics and biochemical analyses further revealed a global impact of RBX2 deficiency on the mitochondrial proteome and identified several mitochondrial proteins as its putative substrates. These findings identify RBX2-CRL5 as a mitochondrial Ub ligase that controls mitophagy under physiological conditions in a PARKIN-independent, PINK1-dependent manner, thereby regulating cardiac homeostasis.

pathology↗

bioRxiv2024

A computational and multi-brain signature for aberrant social coordination in schizophrenia

Social functioning impairment is a core symptom of schizophrenia (SCZ). Yet, the computational and neural mechanisms of social coordination in SCZ under real-time and naturalistic settings are poorly understood. Here, we instructed patients with SCZ to coordinate with a healthy control (HC) in a joint finger-tapping task, during which their brain activity was measured by functional near-infrared spectroscopy simultaneously. The results showed that patients with SCZ exhibited poor rhythm control ability and unstable tapping behaviour, which weakened their interpersonal synchronization when coordinating with HCs. Moreover, the dynamical systems modelling revealed disrupted between-participant coupling when SCZ patients coordinated with HCs. Importantly, increased inter-brain synchronization was identified within SCZ-HC dyads, which positively correlated with behavioural synchronization and successfully predicted dimensions of psychopathology. Our study suggests that SCZ individuals may require stronger neural alignment to compensate for deficiency in their coordination ability. This hyperalignment may be relevant for developing inter-personalized treatment strategies.

neuroscience↗

bioRxiv2023

Two transcriptional cascades orchestrate cockroach leg regeneration

The mystery of appendage regeneration has fascinated humans for centuries, while the regulatory mechanisms remain unclear. In this study, a transcriptional landscape of regenerating leg was established in the American cockroach, Periplaneta americana, an ideal model for appendage regeneration with remarkable regeneration capacity. Through a large-scale in vivo screening, we identified multiple signaling pathways and transcription factors (TFs) controlling leg regeneration. Specifically, zfh-2 and bowl, which have not been previously implicated in appendage regeneration, contributes to blastema proliferation and morphogenesis in two novel transcriptional cascades BMP/JAK-STAT-zfh-2-bab1/B-H2/Lim1 and Notch-drm/bowl-bab1. Notably, zfh-2 was found working as a direct target of BMP signaling to promote cell proliferation in the blastema. These mechanisms might be conserved in the appendage regeneration of vertebrates from an evolutionary perspective. Overall, our findings reveal that two crucial transcriptional cascades orchestrate distinct cockroach leg regeneration processes, significantly advancing the comprehension of molecular mechanism in appendage regeneration.

developmental biology↗

bioRxiv2023

TranSiGen: Deep representation learning of chemical-induced transcriptional profile

With the advancement of high-throughput RNA sequencing technologies, the use of chemical-induced transcriptional profiling has greatly increased in biomedical research. However, the usefulness of transcriptomics data is limited by inherent random noise and technical artefacts that may cause systematical biases. These limitations make it challenging to identify the true signal of perturbation and extract knowledge from the data. In this study, we propose a deep generative model called Transcriptional Signatures Generator (TranSiGen), which aims to denoise and reconstruct transcriptional profiles through self-supervised representation learning.TranSiGen uses cell basal gene expression and compound molecular structure representation to infer the chemical-induced transcriptional profile. Results demonstrate the effectiveness of TranSiGen in learning and predicting differential expression genes. The representation derived from TranSiGen can also serve as an alternative phenotype information, with applications in ligand-based virtual screening, drug response prediction, and phenotype-based drug repurposing. We envisage that integrating TranSiGen into the drug discovery and mechanism research pipeline will promote the development of biomedicine.

bioinformatics↗

bioRxiv2023

Structural insights into the distinct protective mechanisms of human antibodies targeting ZIKV NS1

Zika virus (ZIKV) Non-structural protein 1 (NS1) plays an essential role in viral replication and immune evasion. Our understanding of the differential protective mechanism of NS1-targeting antibodies is limited. Here, we determined the cryoEM structures of ZIKV NS1 in complex with two group antibodies at 2.6-2.9[A]. Group I antibodies (3G2 and 4B8) potently recognize cell surface form of NS1 and multiple oligomeric forms of NS1 by occupy the epitopes on outer surface of dimeric NS1. IgG and Fab from group I antibodies completely abrogate sNS1-mediated endothelial dysfunction in vitro. Group II antibodies (4F10, 2E11, and 14G5) recognize the previously reported epitopes in distal end of the {beta}-ladder domain of monomeric NS1, and their blockade efficiency depends on the affinity with NS1 protein. These findings elucidate the correlation between the epitope recognition and the protective efficacy of anti-NS1 antibodies and highlight the distinct mechanisms of therapeutic potential of 3G2 and 4B8.

microbiology↗

bioRxiv2023

Systematic Investigation of Machine Learning on Limited Data: A Study on Predicting Protein-Protein Binding Strength

The application of machine learning techniques in biological research, especially when dealing with limited data availability, poses significant challenges. In this study, we leveraged advancements in method development for predicting protein-protein binding strength to conduct a systematic investigation into the application of machine learning on limited data. The binding strength, quantitatively measured as binding affinity, is vital for understanding the processes of recognition, association, and dysfunction that occur within protein complexes. By incorporating transfer learning, integrating domain knowledge, and employing both deep learning and traditional machine learning algorithms, we mitigate the impact of data limitations and make significant advancements in predicting protein-protein binding affinity. In particular, we developed over 20 models, ultimately selecting three representative best-performing ones that belong to distinct categories. The first model is structure-based, consisting of a random forest regression and thirteen handcrafted features. The second model is sequence-based, employing an architecture that combines transferred embedding features with a multilayer perceptron. Finally, we created an ensemble model by averaging the predictions of the two aforementioned models. The comparison with other predictors on three independent datasets confirmed the significant improvements achieved by our models in predicting protein-protein binding affinity. The source codes for these three models are available at https://github.com/minghuilab/BindPPI.

bioinformatics↗

bioRxiv2023

Cooperative progression of colitis and leukemia modulated by clonal hematopoiesis via PTX3/IL-1β pro-inflammatory signaling

Clonal hematopoiesis (CH) is considered an important risk factor for all-cause mortality and the development of multiple chronic diseases including hematological neoplasms, cardiovascular diseases, and potentially a range of autoimmune or immune-deficiency diseases. Mutations in TET2 are one of the first identified, most important, and prevalent genetic drivers of CH. However, cooperative factors and mechanisms underlying TET2-deficiency related CH (TedCH) remain largely unknown. Recently, it has been suggested that certain diseases occurred before TedCH and promote TedCH trajectory on the contrary, indicating that diseases in non-hematopoietic organs may act as environmental non-genetic drivers of CH. To clarify the relationships between immune-dysfunctional diseases and CH, here we tested the impact of various challenges on TedCH. We found that expedited TedCH depended on establishment of an inflammatory environment. Primary or chimeric Tet2-mutant mice spontaneously developed co-symptoms reminiscent of human chronic colitis and myeloid leukemia, which was exacerbated by feeding with DSS, an experimental inducer of ulcerative colitis. Single cell RNA-seq (scRNA-seq) analysis reveals in depth the damage of colon in the Tet2-mutant mice in physiological conditions or fed with DSS, along with increase of dysbacteriosis indicated by gut microbiome analysis. Results from colon scRNA-seq from both mouse and human highlight the important roles of PTX3/IL-1{beta} pro-inflammatory signaling in promoting colitis or leukemia. Finally, TedCH trajectory and inflammation in colon and bone marrow were ameliorated by treatment of IL-1R1 inhibitor Anakinra. Our study suggests that PTX3/IL-1{beta} signaling and clonal hematopoiesis cooperate and play important roles in gut-bone marrow axis and related diseases including colitis and leukemia. HighlightsO_LICertain environmental factors, such as Dextran Sulfate Sodium (DSS), an experimental inducer of ulcerative colitis, promote TedCH C_LIO_LIColitis and leukemia are spontaneously and simultaneously developed in Tet2-defficient primary or chimeric mice, along with increased pathogenic gut microbiomes, indicating an aberrant gut-bone marrow axis in the mutant mice. C_LIO_LISingle cell RNA-seq analysis reveals enhanced PTX3, a soluble pattern recognition molecule and IL-1{beta} pro-inflammatory signaling in colitis and leukemia. C_LIO_LIThe In vivo function of the PTX3/IL-1{beta} pro-inflammatory signaling in TedCH is indicated in human colitis and validated in experimental settings. C_LI

immunology↗

bioRxiv2023

Exploring the parity paradox: Differential effects on neuroplasticity and neuroinflammation by APOEe4 genotype at middle-age

Female sex and Apolipoprotein E (APOE) {varepsilon}4 genotype are top non-modifiable risk factors for Alzheimers disease (AD). Although female-unique experiences like parity (pregnancy and motherhood) have positive effects on neuroplasticity at middle age, previous pregnancy may also contribute to AD risk. To explore these seemingly paradoxical long-term effects of parity, we investigated the impact of parity with APOE{varepsilon}4 genotype by examining behavioural and neural biomarkers of brain health in middle-aged female rats. Our findings show that primiparous (parous one time) hAPOE{varepsilon}4 rats display increased use of a non-spatial cognitive strategy and exhibit decreased number and recruitment of new-born neurons in the ventral dentate gyrus of the hippocampus in response to spatial working memory retrieval. Furthermore, primiparity and hAPOE{varepsilon}4 genotype synergistically modulate neuroinflammatory markers in the ventral hippocampus. Collectively, these findings demonstrate that previous parity in hAPOE{varepsilon}4 rats confers an added risk to present with reduced activity and engagement of the hippocampus as well as elevated pro-inflammatory signaling, and underscores the importance of considering female-specific factors and genotype in health research. O_LSTHighlightsC_LSTO_LIhAPOE{varepsilon}4 rats made more errors and used a non-spatial cognitive strategy C_LIO_LIPrimiparous hAPOE{varepsilon}4 rats increased use of a non-spatial cognitive strategy C_LIO_LIParity increased neurogenesis in wildtype rats, but decreased it in hAPOE{varepsilon}4 rats C_LIO_LIPrimiparous hAPOE{varepsilon}4 rats had less active new neurons in response to memory retrieval C_LIO_LIParity and hAPOE{varepsilon}4 affect the neuroimmune milieu in a region-specific manner C_LI

neuroscience↗

bioRxiv2023

Endosome-ER Interactions Define a Cellular Energy Landscape to Guide Cargo Transport

Molecular motor-driven cargo must navigate a complex intracellular environment, which is often crowded, heterogeneous and fluctuating, to fulfill their diverse functions in a cell. To meet these challenges, most cargo display qualitatively similar transport behavior, that is, random switching between states of diffusive "jiggling" movement (off-state) and states of directed "runs" (on-state). The physical picture of this 2-state motion and their regulation in a cell are not well understood. Here, by using single-particle tracking and motion-states dissection, we present a statistical analysis of the 2-state motion of epidermal growth factor receptor (EGFR)-endosomes in living cells. From a thorough analysis of a large volume of EGFR-endosome trajectories, we reveal that their lifetime in both states feature an exponential distribution with its probability density function (PDF)-amplitude varied by more than three decades. We show that their characteristic time, on-state probability, velocity and off-state diffusion coefficient are spatially regulated, and are probably contributed by the endoplasmic reticulum (ER) network via its spatially varying membrane densities and interactions with the cargo. We further propose a 2-state transport model to describe the complex, spatially varying transport dynamics of EGFR-endosomes in a cell. Our findings suggest that the ER network may play an essential role in constructing a cellular-level free-energy landscape {Delta}G(r) to spatially guide cargo transport.

biophysics↗