Biology subjects

Chen, S.

Publications and source records attributed to Chen, S..

At least 361 records · Page 20Linked to original sources

bioRxiv2024

Automatic diagnostics of electroencephalography pathology based on multi-domain feature fusion

Electroencephalography (EEG) serves as a practical auxiliary tool deployed to diagnose diverse brain-related disorders owing to its exceptional temporal resolution, non-invasive characteristics, and cost-effectiveness. In recent years, with the advancement of machine learning, automated EEG pathology diagnostics methods have flourished. However, most existing methods usually neglect the crucial spatial correlations in multi-channel EEG signals and the potential complementary information among different domain features, both of which are keys to improving discrimination performance. In addition, latent redundant and irrelevant features may cause overfitting, increased model complexity, and other issues. In response, we propose a novel feature-based framework designed to improve the diagnostic accuracy of multi-channel EEG pathology. This framework first applies a multi-resolution decomposition technique and a statistical feature extractor to construct a salient time-frequency feature space. Then, spatial distribution information is channel-wise extracted from this space to fuse with time-frequency features, thereby leveraging their complementarity to the fullest extent. Furthermore, to eliminate the redundancy and irrelevancy, a two-step dimension reduction strategy, including a lightweight multi-view time-frequency feature aggregation and a non-parametric statistical significance analysis, is devised to pick out the features with stronger discriminative ability. Comprehensive examinations of the Temple University Hospital Abnormal EEG Corpus V. 2.0.0 demonstrate that our proposal outperforms state-of-the-art methods, highlighting its significant potential in clinically automated EEG abnormality detection.

bioengineering↗

bioRxiv2024

OsWHY1/OsTRXz/OsMORFs complex is essential for RNA modification and early chloroplast development in rice

WHIRLY (WHY) proteins are single-stranded DNA/RNA-binding proteins that play multifaceted roles in various plant species. The regulatory mechanisms of WHY proteins in rice remains blank. Here we demonstrate that OsWHY1 in rice is required for early chloroplast development. CRISPR/Cas9-generated oswhy1 knockout lines displayed albino seedling phenotypes, abnormal chloroplast structure and comprised redox balance in leaves. OsWHY1 interacts with multiple plastid proteins, including the thioredoxin OsTRXz and two multiple organellar RNA editing factors (OsMORF8 and OsMORF9) in chloroplasts. Accordingly, several plastid genes dependent on plastid-encoded RNA polymerase (PEP) in the oswhy1 mutants were significantly depressed at both transcript and protein levels. The editing of rps14 transcripts and splicing of rpl2, along with their protein expression, were defective in the oswhy1 mutants. OsWHY1 exhibited RNA-binding activity, specifically binding to rps14 and rpl2 precursor RNAs, which underscores its role as a post-transcriptional regulator essential for normal protein synthesis in chloroplasts. Loss-of- function mutants of either OsWHY1 or OsMORF9 and OsTRXz displayed albino phenotypes, disrupted H2O2 homeostasis, and defective RNA processing in rps14 and rpl2, suggesting the OsWHY1-OsTRXz-OsMORFs regulatory module is vital for maintaining chloroplast stability and integrity through its RNA-binding activity and its role in recruiting OsTRXz and OsMORFs to ensure proper RNA modification. One sentence summaryOsWHY1 is integral to chloroplast development in rice through its RNA-binding activity and its role in recruiting OsTRXz and OsMORFs to ensure proper RNA modification.

plant biology↗

bioRxiv2024

Androgen deprivation-mediated activation of AKT is enhanced in prostate cancer with TMPRSS2:ERG fusion

TMPRSS2:ERG gene fusion (T:E fusion) in prostate adenocarcinoma (PCa) puts ERG under androgen receptor (AR) regulated TMPRSS2 expression. T:E fusion is associated with PTEN loss, and is highly associated with decreased INPP4B expression, which together may compensate for ERG-mediated suppression of AKT signaling. We confirmed in PCa cells and a mouse PCa model that ERG suppresses IRS2 and AKT activation. In contrast, ERG downregulation did not increase INPP4B, suggesting its decrease is indirect and reflects selective pressure to suppress INPP4B function. Notably, INPP4B expression is decreased in PTEN-intact and PTEN-deficient T:E fusion tumors, suggesting selection for a nonredundant function. As ERG in T:E fusion tumors is AR regulated, we further assessed whether AR inhibition increases AKT activity in T:E fusion tumors. A T:E fusion positive PDX had increased AKT activity in vivo and response to AKT inhibition in vitro after androgen deprivation. Moreover, two clinical trials of neoadjuvant AR inhibition prior to radical prostatectomy showed greater increases in AKT activation in the T:E fusion positive versus negative tumors. These findings indicate that AKT activation may mitigate the efficacy of AR targeted therapy in T:E fusion PCa, and that these patients may most benefit from combination therapy targeting AR and AKT.

cancer biology↗

bioRxiv2024

Screening macrocyclic peptide libraries by yeast display allows control of selection process and affinity ranking

Macrocyclic peptides provide an attractive modality for drug development due to their ability to bind challenging targes, their small size, and amenability to powerful in vitro evolution techniques such as phage or mRNA display. While these technologies proved capable of generating and screening extremely large libraries and yielded ligands to already many targets, they often do not identify the best binders within a library due to the difficulty of monitoring performance and controlling selection pressure. Furthermore, only a small number of enriched ligands can typically be characterised due to the need of chemical peptide synthesis and purification prior to characterisation. In this work, we address these limitations by developing a yeast display-based strategy for the generation, screening and characterisation of structurally highly diverse disulfide-cyclised peptides. Analysis and sorting by quantitative flow cytometry enabled monitoring the performance of millions of individual macrocyclic peptides during the screening process and allowed us identifying macrocyclic peptide ligands with affinities in the low micromolar to high picomolar range against five highly diverse protein targets. X-ray analysis of a selected ligand in complex with its target revealed optimal shape complementarity, large interaction surface, constrained peptide backbones and multiple inter- and intra-molecular interactions, rationalising the high affinity and exquisite selectivity. The novel technology described here offers a facile, quantitative and cost-effective alternative to rapidly and efficiently generate and characterise fully genetically encoded macrocycle peptide ligands with sufficiently good binding properties to even therapeutically relevant targets.

biochemistry↗

bioRxiv2024

ER stress-induced TREM2 downregulation exacerbates platelet activation and myocardial infarction in patients with coronary artery disease

Coronary artery disease (CAD) is characterized by the chronic immune-inflammation, excessive endoplasmic reticulum (ER) stress, and platelet hyperactivity; however, whether there is a signaling hub linking these events remains unclear. Here, we identified that triggering receptor expressed on myeloid cells 2 (TREM2), an important pattern recognition receptor of the innate immune system, may serve as one such hub. We found that platelets expressed TREM2 and platelets from CAD patients had decreased TREM2 expression compared to healthy subjects. Decreased TREM2 is associated with platelet hyperactivity in CAD patients. This decrease could be due to excessive ER stress, which downregulated TREM2 through the CHOP-C/EBP axis. Loss of TREM2 not only enhanced platelet activation in response to ADP, collagen, and collagen-related peptide (CRP), but also amplified the platelet inflammatory response. Loss of TREM2 exacerbated mouse mesenteric arterial thrombosis and aggravated experimental myocardial infarction (MI). Moreover, a TREM2-activating antibody inhibited platelet activation, alleviated arterial thrombosis and pulmonary embolism. In addition, TREM2-activating antibody exhibited cardioprotective roles against experimental MI and reduced the inflammatory burden. Mechanistically, TREM2/DAP12/SHIP1 axis negatively regulated platelet activation through reducing PIP3 levels and inhibiting Akt phosphorylation. We also provided evidence supporting sphingosine-1-phospage (S1P) as a physiological agonist of TREM2. In summary, we find that TREM2 connects chronic immune-inflammation, excessive ER stress, and platelet hyperactivity in CAD patients. Downregulating TREM2 by ER stress exacerbates platelet activation and amplifies inflammation response in patients with CAD. TREM2-activating antibodies may have therapeutic potential for CAD patients. Key PointsO_LIPlatelets from CAD patients have decreased TREM2 expression, which is caused by ER stress and associated with platelet hyperactivity. C_LIO_LIS1P-TREM2-SHIP1 pathway inhibits platelet activation, alleviates arterial thrombosis, and exhibits cardioprotective roles against experimental myocardial infarction. C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=88 SRC="FIGDIR/small/608887v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@1e21f2eorg.highwire.dtl.DTLVardef@6d427forg.highwire.dtl.DTLVardef@128af74org.highwire.dtl.DTLVardef@16f48c_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOVisual Abstract.C_FLOATNO Downregulation of platelet TREM2 caused by ER stress in CAD patients leads to platelet hyperactivity and aggravates myocardial ischemia, which is rescued by TREM2-activating antibody. Excessive ER stress in CAD upregulates CHOP, which dimerizes with C/EBP, a transcription factor of TREM2, decreases TREM2 transcription and expression in megakaryocytes and further in platelets. TREM2/DAP12/SHIP1/Akt pathway negatively regulates platelet activation; decreased TREM2 thus aggravates platelet hyperactivity, inflammation, and myocardial infarction, which can be rescued by TREM2 activation including antibody or the small molecule agonist. Physiologically, S1P released from platelet granules is an endogenous agonist of TREM2. C_FIG

pharmacology and toxicology↗

bioRxiv2024

Berberine is a novel mitochondrial calcium uniporter (MCU) inhibitor that disrupts MCU-EMRE assembly

The mitochondrial calcium uniporter (MCU) complex mediates Ca2+ entry into mitochondrial, which plays a crucial role in regulating cellular energy metabolism and apoptosis. Dysregulation of MCU is implicated in various diseases, such as neurodegenerative disorders, cardiac diseases and cancer. Despite its importance, developing specific and clinically viable MCU inhibitors has been challenging. Here, we identify Berberine, a well-established drug with a documented safety profile, as a potent MCU inhibitor through a virtual screening of an FDA-approved drug library. Berberine localizes within mitochondria and directly binds to the juxtamembrane loop domain of MCU. This binding disrupts the interaction of MCU with its essential regulator, EMRE, thereby inhibiting rapid Ca2+ entry into the mitochondria. Notably, Berberine pretreatment reduces mitochondrial Ca2+ overload and mitigate ischemia/reperfusion-induced myocardial injury in mice. Our findings establish Berberine as a potent MCU inhibitor, offering a safe therapeutic strategy for diseases associated with dysregulated mitochondrial calcium homeostasis.

cell biology↗

bioRxiv2024

Engineered Nanotopographies Induce Transient Openings in the Nuclear Membrane

Materials with engineered nano-scale surface topographies, such as nanopillars, nanoneedles, and nanowires, mimic natural structures like viral spike proteins, enabling them to bypass biological barriers like the plasma membrane. These properties have led to applications in nanoelectronics for intracellular sensing and drug delivery platforms, some of which are already in clinical trials. Here, we present evidence that nanotopographic materials can induce transient openings in the nuclear membranes of various cell types without penetrating the cells, breaching the nucleo-cytoplasmic barrier and allowing uncontrolled molecular exchange across the nuclear membrane. These openings, induced by nanoscale curvature, are temporary and repaired through ESCRT-mediated mechanisms. Our findings suggest a potential for nano topographic materials for direct nuclear sensing and delivery, holding promise for improving the delivery, efficiency, and safety of therapeutic agents to the nucleus.

bioengineering↗

bioRxiv2024

ORMDL3 restrains type-I interferon signaling and anti-tumor immunity by promoting RIG-I degradation

Mounting evidence has demonstrated the genetic association of ORMDL3 (ORMDL Sphingolipid Biosynthesis Regulator 3) gene polymorphisms with bronchial asthma and a diverse set of inflammatory disorders. However, its role in type I interferon (IFN) signaling remains poorly defined. Herein, we report that ORMDL3 is a negative modulator of the type I IFN signaling by interacting with MAVS (Mitochondrial Antiviral Signaling protein) and subsequently promoting the proteasome-mediated degradation of RIG-I (Retinoic Acid-Inducible Gene I). Immunoprecipitation coupled with mass spectrometry (IP-MS) assays uncovered that ORMDL3 binds to USP10 (Ubiquitin-Specific Protease 10), which forms a complex with and stabilizes RIG-I through decreasing its K48-linked ubiquitination. ORMDL3 thus disrupts the interaction between USP10 and RIG-I, thereby promoting RIG-I degradation. Additionally, subcutaneous syngeneic tumor models in C57BL/6 mice revealed that inhibition of ORMDL3 enhances anti-tumor efficacy by augmenting the proportion of cytotoxic CD8 positive T cells and IFN production in the tumor microenvironment (TME). Collectively, our findings reveal the pivotal roles of ORMDL3 in maintaining antiviral innate immune responses and anti-tumor immunity.

molecular biology↗

bioRxiv2024

CaMutQC: An R Package for Integrative Quality Control of Cancer Somatic Mutations

The quality control and filtration of cancer somatic mutations (CAMs), including the elimination of false positives resulting from technical bias and the selection of key mutation candidates, is crucial for downstream analysis in cancer genomics. Due to diverse needs and the absence of standardized filtering criteria, the filtering strategies employed vary from study to study, often leading to reduced efficiency, accuracy, and comparability across similar analyses. Here we present CaMutQC, a heuristic quality control and soft-filtering R/Bioconductor package for CAMs. With CaMutQC, the removal of false positives, selection of potential mutation candidates, and Tumor Mutation Burden estimation can be executed in a single line of code, using default or customized parameters. A filter report and a code log generated after the filtration process assist with recording and comparison. The application of CaMutQC on a Whole-exome Sequencing (WES) benchmark dataset demonstrated its impressive capability by eliminating 85.55% of false positive mutations while retaining 90.72% of true positive mutations. Additionally, an extra 11.56% of true positive mutations were recused by the union strategy embedded in CaMutQC. CaMutQC is now available through Bioconductor at https://bioconductor.org/packages/CaMutQC/ under the GPL v3 license, and it will be updated regularly to incorporate top filtration strategy and parameter sets shared within the community.

bioinformatics↗

bioRxiv2024

Therapeutic targeting of Syndecan-1 axis overcomes acquired resistance to KRAS-targeted therapy in gastrointestinal cancers

The therapeutic benefit of recently developed mutant KRAS (mKRAS) inhibitors has been limited by the rapid onset of resistance. Here, we aimed to delineate the mechanisms underlying acquired resistance to mKRAS inhibition and identify actionable targets for overcoming this clinical challenge. Previously, we identified Syndecan-1 (SDC1) as a key effector for pancreatic cancer progression whose surface expression is driven by mKRAS. By leveraging both pancreatic and colorectal cancer models, we found that surface SDC1 expression was initially diminished upon mKRAS inhibition, but recovered in tumor cells that bypass mKRAS dependency. Functional studies showed that these tumors depended on SDC1 for survival, further establishing SDC1 as a driver for the acquired resistance to mKRAS inhibition. Mechanistically, we revealed that the YAP1-SDC1 axis was the major driving force for bypassing mKRAS dependency to sustain nutrient salvage machinery and tumor maintenance. Specifically, YAP1 activation mediated the recovery of SDC1 localization on cell surface that sustained macropinocytosis and enhanced the activation of multiple RTKs, promoting resistance to KRAS-targeted therapy. Overall, our study has provided the rationale for targeting the YAP-SDC1 axis to overcome resistance to mKRAS inhibition, thereby revealing new therapeutic opportunities for improving the clinical outcome of patients with KRAS-mutated cancers.

cancer biology↗

bioRxiv2024

Heat Shock Factor Regulation of Antimicrobial Peptides Expression Suggests a Conserved Defense Mechanism Induced by Febrile Temperature in Arthropods

Temperature is a critical factor influencing the outbreak and progression of viral diseases in organisms. Febrile temperatures have been shown to enhance immune competence and reduce viral replication in various species. However, the underlying mechanisms remain largely unknown. In this study, we investigate the molecular mechanisms by which elevated temperatures confer resistance to viral infections, focusing on the role of heat shock factor 1 (HSF1) in regulating antimicrobial effectors rather than the traditional target genes molecular chaperones. Using shrimp Litopenaeus vannamei as a model, we demonstrate that febrile temperatures induce HSF1, which in turn upregulates antimicrobial peptides (AMPs) that target viral envelope proteins and inhibit viral replication. Importantly, this is the first to show that HSF1 directly binds to the heat shock elements (HSE) motifs of AMPs both in shrimp and Drosophila S2 cells, suggesting this may be a conserved regulatory mechanism in arthropods. Additionally, our findings highlight the role of HSF1 beyond the classical heat shock response, revealing its critical function in modulating innate immunity. These insights provide new avenues for managing viral infections in aquaculture and other settings by leveraging environmental temperature control.

immunology↗

bioRxiv2024

Human Vascularized Macrophage-Islet Organoids to Model Immune-Mediated Pancreatic β cell Pyroptosis upon Viral Infection

There is a paucity of human models to study immune-mediated host damage. Here, we utilized the GeoMx spatial multi-omics platform to analyze immune cell changes in COVID-19 pancreatic autopsy samples, revealing an accumulation of proinflammatory macrophages. Single cell RNA-seq analysis of human islets exposed to SARS-CoV-2 or Coxsackievirus B4 (CVB4) viruses identified activation of proinflammatory macrophages and {beta} cell pyroptosis. To distinguish viral versus proinflammatory macrophage-mediated {beta} cell pyroptosis, we developed human pluripotent stem cell (hPSC)-derived vascularized macrophage-islet (VMI) organoids. VMI organoids exhibited enhanced marker expression and function in both {beta} cells and endothelial cells compared to separately cultured cells. Notably, proinflammatory macrophages within VMI organoids induced {beta} cell pyroptosis. Mechanistic investigations highlighted TNFSF12-TNFRSF12A involvement in proinflammatory macrophage-mediated {beta} cell pyroptosis. This study established hPSC- derived VMI organoids as a valuable tool for studying immune cell-mediated host damage and uncovered mechanism of {beta} cell damage during viral exposure.

developmental biology↗

bioRxiv2024

A biodegradable and restorative peripheral neural interface for the interrogation of neuropathic injuries

Monitoring the early-stage healing of severe traumatic nerve injuries is essential to gather physiological and pathological information for timely interventions and optimal clinical outcomes. While implantable peripheral nerve interfaces provide direct access to nerve fibers for precise interrogation and modulation, conventional non-degradable designs pose limited utilization in nerve injury rehabilitation. Here, we introduce a biodegradable and restorative neural interface for wireless real-time tracking and recovery of long-gap nerve injuries. Leveraging machine learning techniques, this electronic platform deciphers nerve recovery status and identifies traumatic neuroma formation at the early phase, enabling timely intervention and significantly improved therapeutic outcomes. The biodegradable nature of the device eliminates the need for retrieval procedures, reducing infection risks and secondary tissue damage. This research sheds light on bioresorbable multifunctional peripheral nerve interfaces for probing neuropathic injuries, offering vital information for early diagnosis and therapeutic intervention.

bioengineering↗

bioRxiv2024

Nuclear Argonaute protein NRDE-3 switches small RNA binding partners during embryogenesis coincident with the formation of SIMR granules

RNA interference (RNAi) is a conserved gene regulation mechanism that utilizes the Argonaute protein and their associated small RNAs to exert regulatory function on complementary transcripts. While the majority of germline-expressed RNAi pathway components reside in perinuclear germ granules, it is unknown whether and how RNAi pathways are spatially organized in other cell types. Here we find that the small RNA biogenesis machinery is spatially and temporally organized during embryogenesis. Specifically, the RNAi factor, SIMR-1, forms visible concentrates during mid-embryogenesis that contain an RNA-dependent RNA polymerase, a poly-UG polymerase, and the unloaded nuclear Argonaute protein, NRDE-3. We also observe that many other RNAi factors form foci in embryonic cells distinct from "SIMR granules", including the Argonaute protein CSR-1, underscoring a potential role for cytoplasmic concentrates of RNAi factors to promote gene regulation in embryos. Curiously, coincident with the appearance of the SIMR granules, the small RNAs bound to NRDE-3 switch from predominantly CSR-class 22G-RNAs to ERGO-dependent 22G-RNAs. Prior work has shown that NRDE-3 binds ERGO-dependent 22G-RNAs in the somatic cells of larvae and adults to silence ERGO-target genes; here we demonstrate that NRDE-3-bound, CSR-class 22G-RNAs repress transcription in oocytes. Thus, our study defines two separable roles for NRDE-3, targeting germline-expressed genes during oogenesis to promote global transcriptional repression, and switching during embryogenesis to repress recently duplicated genes and retrotransposons in somatic cells, highlighting the plasticity of Argonaute proteins and the need for more precise temporal characterization of Argonaute-small RNA interactions.

cell biology↗

bioRxiv2024

CRISPR-mediated chromosome deletion facilitates genetic mapping of Vip3Aa resistance gene within complex genomic region in an invasive global pest

Connecting genetic variation to phenotypes and understanding the underlying biological mechanisms has been a fundamental goal of biological genetics. Here, we used the association analysis to identify a Vip3Aa resistance-associated genomic region in a strain of fall armyworm, JC-R, which exhibits >5000-fold resistance to the Bt toxin Vip3Aa. However, through various analytical approaches and fine-scale mapping across different populations, we demonstrated that this genomic region exhibits strong genetic linkage. The chromosome-level genome of JC-R and its parent strain JC-S were assembled, and extensive structural variations in the linkage regions were identified, which could be responsible for maintaining the linkage. To identify the causal variation within this linked region, a chromosome fragment stepwise knockout strategy based on CRISPR/Cas9 was developed. By crossing with the resistant strain and phenotyping segregating offspring on Vip3Aa-containing diet, we identified a chromosomal segment, KO8, containing the resistant gene. Subsequently, we conducted a comprehensive analysis of the variations in the KO8 region using multi-omics approaches, including genomic data, RNA-seq, proteomic, PacBio long read Iso-seq, and phosphoproteomic data. This analysis identified multiple variations in the chitin synthase gene CHS2, including amino acid substitution, alternative splicing, and changes in phosphorylation sites. After knocking out the CHS2, larvae exhibited over 6777-fold resistance to Vip3Aa. These results demonstrate that the chromosome fragment stepwise knockout strategy is a viable approach for studying complex genomic regions, and highlight the value of comprehensive analysis of genetic variations using multi-omics data. The identified candidate gene could potentially advance monitoring and management of pest resistance to Vip3Aa.

genetics↗

bioRxiv2024

Adipogenin Dictates Adipose Tissue Expansion by Facilitating the Assembly of a Dodecameric Seipin Complex

Adipogenin (Adig) is an evolutionarily conserved microprotein and is highly expressed in adipose tissues and testis. Here, we identify Adig as a critical regulator for lipid droplet formation in adipocytes. We determine that Adig interacts directly with seipin, leading to the formation of a rigid complex. We solve the structure of the seipin/Adig complex by Cryo-EM at 2.98[A] overall resolution. Surprisingly, seipin can form two unique oligomers, undecamers and dodecamers. Adig selectively binds to the dodecameric seipin complex. We further find that Adig promotes seipin assembly by stabilizing and bridging adjacent seipin subunits. Functionally, Adig plays a key role in generating lipid droplets in adipocytes. In mice, inducible overexpression of Adig in adipocytes substantially increases fat mass, with enlarged lipid droplets. It also elevates thermogenesis during cold exposure. In contrast, inducible adipocyte-specific Adig knockout mice manifest aberrant lipid droplet formation in brown adipose tissues and impaired cold tolerance.

cell biology↗

bioRxiv2024

Co-recognition of histone acetylation and H3K4 trimethylation by GTE4-EML complex in Arabidopsis

Although histone acetylation and H3K4 trimethylation (H3K4me3) are well-known histone marks associated with active transcription, how they cooperate to regulate transcription remains largely unclear in plants. Our study revealed that the Bromodomain and Extra-terminal (BET) protein GTE4 binds to acetylated histone and forms a complex with the redundant H3K4me3-binding EMSY-Likeproteins EML1 or EML2 (EML1/2) in Arabidopsis thaliana. The eml1 eml2 (eml1/2) double mutant exhibited a morphological phenotype similar to the gte4 mutant, and most of the gte4-mediated differentially expressed genes were co-regulated in the eml1/2 mutant. Through chromatin immunoprecipitation followed by deep sequencing (ChIP-seq), we found that GTE4 and EML2 co-occupy protein-coding genes enriched with both histone acetylation and H3K4me3, exhibiting a synergistic effect on the association of the GTE4-EML complex with chromatin. The association of GTE4 with chromatin requires both the Bromodomain and the EML-interacting domain. This study identified a previously uncharacterized complex and uncovered how it cooperatively recognizes histone acetylation and H3K4me3 to facilitate gene transcription at the whole-genome level in Arabidopsis.

molecular biology↗

bioRxiv2024

Negatively Charged alpha-Synuclein Condensate Modulates Partitioning of Molecules

-Synuclein (Syn) aggregation via liquid-liquid phase separation has recently emerged as a crucial mechanism underlying amyloid fibril formation implicated in Parkinsons disease. However, comprehensive investigations of the physico-chemical properties of Syn condensate remains incomplete. Here, we showed that Syn condensate possesses a highly negative electrostatic potential that spans the whole condensate. This property causes differential partitioning of dye-labeled Syn as well as fluorescent molecules by an order of magnitude depending on their net charges. Consistent with this, the phase separation propensity of Syn is governed by a delicate balance between self-association of Syn and electrostatic repulsion, hence is antagonized by excess negative charge. We further demonstrated that, in differentiated neuron-like SH-SY5Y cells, Syn also forms negatively charged condensate. Our results highlighted the significant impact of Syn condensates electrostatic potential on molecular partitioning, hence calling for close examination of the electrostatic property of other biomolecular condensates.

biophysics↗