Biology subjects

Jiang, M.

Publications and source records attributed to Jiang, M..

At least 55 records · Page 3Linked to original sources

bioRxiv2025

Screening of a kinase library in human Huntington disease iPSC derived striatal precursor neurons reveals a neuroprotective effect of PKC alpha and PKC beta1 inhibition

The loss of striatal medium spiny neurons is a hallmark of Huntingtons disease (HD). To identify potential disease-modifying treatments, we previously developed a human neuronal model by immortalizing and differentiating HD patient-derived iPSCs into highly homogeneous striatal precursor neurons (ISPNs). Using a 96-well screening platform, and two rounds of re-screening, we tested a kinase inhibitor library and identified 5 compounds that protected HD ISPNs from mutant huntingtin (mHTT)-induced toxicity. Among these, we prioritized the PKC-/{beta}1 inhibitor GO6976, which rescued HD ISPNs from mHTT toxicity in a dose-dependent manner. Further, we found increased phosphorylation of PKC- and PKC-{beta}1 in HD cells and tissues, while their overexpression was toxic to HD ISPNs. Knockdown of PKC-/{beta}1 protected the neurons, and both isoforms interacted and colocalized with HTT. These results suggest that PKC-/{beta}1 plays a role in HD neurodegeneration, and that inhibiting their activity may offer a potential therapeutic approach for HD. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=194 SRC="FIGDIR/small/677178v2_ufig1.gif" ALT="Figure 1"> View larger version (48K): org.highwire.dtl.DTLVardef@256d6org.highwire.dtl.DTLVardef@1931e7borg.highwire.dtl.DTLVardef@1b6598borg.highwire.dtl.DTLVardef@b0bbb5_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIHD patient-derived iPSC-based striatal precursor neurons (ISPNs) were used to screen and identify neuroprotective compounds. C_LIO_LIThe PKC-/{beta}1 inhibitor GO6976 rescues HD ISPNs from mutant huntingtin (HTT)-induced toxicity. C_LIO_LIThe phosphorylation of PKC-/{beta}1 is elevated in HD cell and tissues, and PKC-/{beta}1 interact with both wild-type and mutant huntingtin. C_LIO_LIOverexpression of PKC-/{beta}1 is toxic to HD ISPNs, while its knockdown protects the neurons. C_LI

neuroscience↗

bioRxiv2025

Molecular structure of the ESCRT III-based archaeal CdvAB cell division machinery

Most prokaryotes divide using filaments of the tubulin-like FtsZ protein, while some archaea employ instead ESCRT-III-like proteins and their filaments for cell division and cytokinesis. The alternative archaeal system comprises Cdv proteins and is thought to bear some resemblance to ESCRT-III-based membrane remodelling in other domains of life, including eukaryotes, especially during abscission. Here we present biochemical, crystallographic and cryo-EM studies of the Sulfolobus Cdv machinery. CdvA, an early non-ESCRT component, adopts a PRC-domain/coiled-coil fold and polymerises into long double-stranded helical filaments, mainly via hydrophobic interfaces. Monomeric CdvB adopts the canonical ESCRT-III fold in both a closed and a distinct "semi-open" conformation. Soluble CdvB2 filaments are composed of subunits in the closed state, appearing to transition to the open, active state only when polymerised on membranes. Short N-terminal amphipathic helices in all CdvB paralogues, B, B1 and B2, mediate membrane binding and are required for liposome recruitment in vitro. We provide a molecular overview of archaeal ESCRT-III-based cytokinesis machinery, the definitive demonstration that CdvB proteins are bona fide ESCRT-III homologues and we reveal the molecular basis for membrane engagement. Thus, we illuminate conserved principles of ESCRT-mediated membrane remodelling and extend them to an anciently diverged archaeal lineage. Significance statementMembrane remodelling by ESCRT-III proteins is a fundamental and conserved process across the tree of life. The archaeal ESCRT-III-based cell division system (Cdv) drives cytokinesis in many archaeal groups, yet the molecular architecture of its components remained unknown, making it difficult to decipher the molecular mechanisms employed for cell division and cytokinesis in these organisms. We present structures of the Cdv machinery in Sulfolobus organisms that have been used previously to study the cell division process. We show that CdvA forms unexpected antiparallel helical filaments, while the ESCRT-III homologues retain the canonical fold we show they share with eukaryotic proteins. We demonstrate that N-terminal helices mediate membrane binding and that membrane contact, rather than polymerisation alone, likely triggers activation of Cdv ESCRT-IIIs.

molecular biology↗

bioRxiv2025

SpatialFinder: A Human-in-the-Loop Vision-Language Framework for Prioritizing High-Value Regions in Spatial Transcriptomics

Sequencing an entire spatial transcriptomics slide can cost thousands of dollars per assay, making routine use impractical. Focusing on smaller regions of interest (ROIs) based on adjacent routine H&E slides offers a practical alternative, but there is (i) no reliable way to identify the most informative areas from standard H&E images alone; and (ii) limited solutions for clinicians to prioritize the microenvironment of their own interests. Here we introduce SpatialFinder, a framework that combines a biomedical vision-language model (VLM) with a human-in-the-loop optimization pipeline to predict gene expression heterogeneity and rank high-value ROIs across routine H&E tissue slides. Evaluated across four Visium HD tissue types, SpatialFinder consistently outperforms baseline VLMs in selecting regions with high cellular diversity and tumor presence, achieving up to 89% correlation with ground truth rankings. These results demonstrate the potential of human-AI collaboration to make spatial transcriptomics more cost-effective and clinically actionable.

bioinformatics↗

bioRxiv2025

Machine-Learning-Assisted Exploration of High Entropy-Atom Nanozyme for Anti-Tumor Immunotherapy by Enhancing Enzyme Activity and Disrupting Dual Energy Metabolism

Despite its potential in cancer therapy, single-atom nanozyme (SAzyme) faces challenges like low atomic loading and rapid cancer metabolism. Here, a high-entropy atom nanozyme (HEAzyme), PtNiBiSnSb-anti-CD36, is designed for efficient anti-tumor immunotherapy. The PtNiBiSnSb HEAzyme, incorporating five SAzyme, demonstrates enhanced peroxidase (POD)-like activity due to its abundant active sites, showing a 7.2-fold increase in catalytic efficiency compared to the structurally analogous PtBi nanozyme. Further integrating of density functional theory calculations and machine learning analysis reveals that the main reason is due to the addition of Ni, Sn, and Sb, which reduced the reaction energy barrier and changed the adsorption energy of surface hydroxyl groups. Moreover, PtNiBiSnSb-anti-CD36 not only inhibits normal metabolic processes by depleting nicotinamide adenine dinucleotide (NADH) through its enhanced NADH-POD-like activity, but also suppresses lipid metabolism by blocking CD36-mediated uptake. The dual metabolic inhibition facilitates the mild photothermal therapy induced by PtNiBiSnSb. In this process, the anti-tumor immune response is amplified by inducing immunogenic cell death and inhibiting the growth of immunosuppressive cells through blocking fatty acid uptake. The proposal of HEAzyme for cancer therapy provides a novel approach to enhance the catalytic activity of SAzymes and deepens the theoretical understanding of HEAzyme in the POD-like reaction process.

cancer biology↗

bioRxiv2025

SARS-CoV-2 envelope protein induces LC3 lipidation via the V-ATPase-ATG16L1 axis

Coronaviruses encode envelope (E), a structural component of the virion that is important for assembly and egress. E has proton channel activity that prevents premature rearrangement of the spike glycoprotein as virions encounter acidic compartments as they exit the cell. How infected cells respond to this pH disruption during coronavirus infection is unknown. Here we show that SARS-CoV-2 E ion channel activity triggers the proton pump V-ATPases to recruit the ATG16L1 complex during infection. This results in ATG8 molecules such as LC3B decorating perturbed compartments. This recruitment of autophagy machinery does not inhibit viral replication, rather SARS-CoV-2 exploits this response. Inhibition of the V-ATPase/ATG16L1 interaction using the Salmonella effector SopF inhibits SARS-CoV-2 replication. Careful distinction between use of the autophagic machinery from canonical macroautophagy is required in order to better understand coronavirus replication and for rational targeting of any potential host-directed therapies.

cell biology↗

bioRxiv2025

Mechanisms of KCNQ1 gating modulation by KCNE1/3 for cell-specific function

KCNQ1 potassium channels are essential for physiological processes such as cardiac rhythm and intestinal chloride secretion. KCNE-family subunits (KCNE1-5) associate with KCNQ1, conferring distinct properties across various tissues. KCNQ1 activation requires membrane depolarization and phosphatidylinositol 4,5-bisphosphate (PIP2) whose cellular levels are controlled by Gq-coupled GPCR activation. While modulation of KCNQ1s voltage-dependent activation by KCNE1/3 is well-characterized, their effects on PIP2-dependent gating of KCNQ1 via GPCR signaling remain less understood. Here we resolved structures of KCNQ1-KCNE1 and reassessed reported KCNQ1-KCNE3 structures with and without PIP2. We revealed that KCNQ1-KCNE1/3 complexes feature two PIP2-binding sites, with KCNE1/3 contributing to a previously overlooked, uncharacterized site involving residues critical for voltage sensor and pore domain coupling. Via this site, KCNE1 and KCNE3 distinctly modulate the PIP2-dependent gating, in addition to the voltage sensitivity, of KCNQ1. Consequently, KCNE3 converts KCNQ1 into a voltage-insensitive PIP2-gated channel governed by GPCR signaling to maintain ion homeostasis in non-excitable cells. KCNE1, by significantly enhancing KCNQ1s PIP2 affinity and resistance to GPCR regulation, forms predominantly voltage-gated channels with KCNQ1 for conducting the slow-delayed rectifier current in excitable cardiac cells. Our study highlights how KCNE1/3 modulates KCNQ1 gating in different cellular contexts, providing insights for tissue-specifically targeting multi-functional channels.

biochemistry↗

bioRxiv2025

Triad-LMF: A Hierarchical Low-Rank Multimodal Fusion Framework for Robust Cancer Subtype Classification Using Multi-Omics Data

Cancer heterogeneity poses a major challenge for accurate molecular subtype classification. Conventional methods often fail to exploit complementary information across multiple omics modalities, leading to overfitting on high-dimensional data and limited representation of subtype heterogeneity. To address this, we propose Triad-LMF, a multiomics integration framework based on low-rank multimodal fusion to improve classification accuracy. Triad-LMF harmonizes heterogeneous omics data and integrates information through a two-stage hierarchical fusion strategy. Local Pairwise Fusion and Global Triadic Fusion are combined via the Two-Feature and Three-Way LMF modules, enabling a gradual transition from local modality interactions to global feature integration. Experimental results show that Triad-LMF consistently outperforms existing methods. UMAP visualization confirms enhanced subtype separability, and SHAP-based analysis highlights biologically meaningful features. Across independent datasets, Triad-LMF demonstrates strong generalization, offering a robust and interpretable framework for multiomics-driven cancer subtype classification.

bioinformatics↗

bioRxiv2025

Dynamic Pathway of Guanidine-III Riboswitch Folding Revealed by Single-Molecule FRET: Mg2+-Assisted Preorganization and Ligand-Induced Kinetic Trapping

Riboswitches are structured RNA elements that regulate gene expression by sensing and binding small molecules. The guanidine-III riboswitch, a critical bacterial regulator responding to guanidine toxicity, undergoes precise conformational changes that remain poorly characterized at a dynamic, mechanistic level. In this study, we employed single-molecule Forster Resonance Energy Transfer (smFRET) coupled with molecular dynamics (MD) simulations to delineate how the guanidine-III riboswitch transitions among distinct conformational states. We identify three principal states [-] an extended (E-state), a compacted prefolded intermediate (P-state), and a folded pseudoknot structure (F-state) [-] with rapid interconversion in the absence of ligand. Magnesium ions significantly stabilize intermediate states via a cooperative, preorganization mechanism, enhancing ligand binding efficiency. Binding of guanidine drastically suppresses the reverse transitions, kinetically trapping the riboswitch into its active folded state primarily through a conformational selection mechanism, with additional contributions from induced-fit dynamics. This work illuminates the unique dynamic pathway by which the guanidine-III riboswitch integrates ionic and ligand cues, ensuring precise gene regulatory responses in bacteria.

biophysics↗

bioRxiv2025

Cold-activated hepatocyte derived exosomes promote BAT thermogenesis through miR-293-5p

The liver-adipose axis serves as a fundamental regulatory network governing systemic lipid homeostasis, with hepatic-derived signals orchestrating adipose tissue plasticity through multimodal mechanisms. Comprehensive elucidation of these bidirectional crosstalk mechanisms may reveal novel therapeutic strategies for metabolic disorders. Our investigation demonstrates that cold exposure induces hepatic secretion of exosomes that potentiate adipose thermogenic activation in both in vitro and in vivo models. This thermogenic potentiation is mechanistically linked to cold-induced upregulation of hepatocyte-derived exosomal miR-293-5p. Notably, pharmacological administration of miR-293-5p agomir significantly attenuates diet- induced obesity and associated metabolic dysregulation in murine models. Through mechanistic interrogation, we identified Tet1 as a direct downstream target of miR- 293-5p, where ectopic Tet1 expression disrupts brown adipose tissue (BAT) thermogenic programming independently of miR-293-5p modulation. Our findings establish cold-activated hepatocyte exosomes as endocrine signaling mediators containing thermogenic microRNA cargos, with miR-293-5p emerging as a regulatory nexus coordinating mitochondrial bioenergetics and systemic energy equilibrium through liver-adipose cross-talk.

genetics↗

bioRxiv2025

Spermatogonia derived RpS13 non-autonomously regulates the cyst cell differentiation via Rho1-mediated adhesion junctions in Drosophila testis

ObjectiveIn the testis of Drosophila, spermatogonia transit-amplification (TA) divisions are necessary for germline proliferation and differentiation. Both the germline and the surrounding somatic cyst cells (SCCs) have a significant influence on these processes. However, the underlying mechanism is largely unknown. MethodsFlies were used to generate tissue-specific gene knockdown. Immunofluorescence was used to determine protein localization and expression pattern. Small interfering RNAs were used to knockdown genes in S2 cells. qRT-PCR was used to examine the relative mRNA expression level. ResultsOur findings indicate that spermatogonial RpS13 regulates cyst cell growth through a non-autonomous manner. In terms of mechanism, RpS13 may regulate the adhesion junctions of the soma-germline via the DE-cad and Arm proteins in addition to dpERK, which is found in SCCs. Interestingly, Rho1 and RpS13 mutually inhibit each other in Drosophila S2 cells. Additionally, Rho1 controlled cell adhesions that rely on DE-cad, Arm, and dpERK and imitated the actions of RpS13 in Drosophila testis. ConclusionAll of these findings implied that during spermatogonia TA-divisions in the testis of Drosophila, RpS13 regulates the development of cyst cells via Rho1-mediated adhesion junctions.

developmental biology↗

bioRxiv2025

Phase separation of Polycomb-like (PCL) proteins drive PRC2 complex condensates to regulate gene expression

Polycomb group (PcG) proteins function as two major multicomponent protein complexes: Polycomb repressive complex 1 (PRC1) and 2 (PRC2) to repress key developmental genes and maintain epigenetic memory of cell identity during development. Phase-separation has long been implicated in PRC1 mediated gene silencing, but it is still unclear whether PRC2 also utilize a similar mechanism to regulate gene expression. Here we report that Polycomb-like (PCL) proteins, PRC2 accessory factors, can phase-separate in vitro and generate dynamic puncta in vivo. Biochemical and cellular analyses reveal that PCL proteins (hereafter referred to as PCLs) have intramolecular interaction between N- and C-terminal domains, which make PCLs into more compact conformations. The intramolecular interaction not only controls the size of the PCLs phase separation droplets, but also affects the chromatin association of PRC2. Finally, we show that CpG islands, key DNA regulatory elements in mammalian promoters, disrupt the N-C intramolecular interaction of PCLs to expose their middle intrinsically disordered regions (IDRs), which in turn trigger PCLs driven PRC2 condensates formation. Together, this study provides a new perspective on the regulation of PRC2 by PCLs, implicating PCLs read CpG islands to fine-tune their oligomerization to overcome the threshold for PRC2 recruitment to corresponding genomic loci via multivalent interaction with CpG islands chromatin.

biochemistry↗

bioRxiv2025

Homoharringtonine Promotes FTO Degradation to Suppress LILRB4-Mediated Immune Evasion in Acute Monocytic Leukemia

Acute monocytic leukemia (AML-M5), a subtype of acute myeloid leukemia, is a highly aggressive malignancy characterized by a poor prognosis, primarily due to the ability of leukemic cells to evade immune surveillance. In this study, we demonstrate that homoharringtonine (HHT), an FDA-approved therapeutic agent for chronic myeloid leukemia (CML), inhibits this immune evasion by targeting the FTO/m6A/LILRB4 signaling pathway in monocytic AML. Utilizing RNA sequencing (RNA-seq) and various functional assays, we reveal that HHT treatment significantly reduces LILRB4 expression at both the RNA and protein levels, suggesting that the effects of HHT on LILRB4 are distinct from its well-established role as a protein synthesis inhibitor. Mechanistically, HHT treatment markedly increases global levels of RNA m6A in THP-1 cells by promoting the degradation of FTO, which subsequently diminishes the expression of its downstream targets, MLL1 and LILRB4. Furthermore, in vitro and in vivo analyses employing monocytic AML cell lines, mouse-derived AML xenograft models, and patient samples collectively support the conclusion that HHT suppresses immune evasion in monocytic AML by reducing LILRB4 expression. Importantly, the downregulation of LILRB4 resulting from HHT treatment enhances the susceptibility of THP-1 cells to CD8+ T cell cytotoxicity, accompanied by increased markers of immune activation. Overall, our findings position HHT as a promising clinical agent for enhancing CD8+ T cell-based cancer immunotherapy by mitigating immune evasion in monocytic AML. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=147 HEIGHT=200 SRC="FIGDIR/small/643466v1_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@e72e5dorg.highwire.dtl.DTLVardef@19519aeorg.highwire.dtl.DTLVardef@1c8f786org.highwire.dtl.DTLVardef@f2a963_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2025

Identification of a neural basis for energy expenditure in the arcuate hypothalamus

Given the evolutionary instinct for caloric intake and the tendency for weight rebound after discontinuing dietary interventions or medications, increasing energy expenditure emerges as an alternative obesity treatment. However, neural regulation of energy expenditure remains poorly understood. Here, we report that a hypothalamic neuronal subtype, characterized by Crabp1 expression, establishes connections with multiple hypothalamic nuclei to regulate energy expenditure in mice. Inactivation of Crabp1 neurons reduces physical activity, body temperature, and adaptive thermogenesis, leading to an obese phenotype. Conversely, activation of these neurons increases energy expenditure and mitigates diet-induced obesity. Structural and functional analyses reveal that Crabp1 neurons promote energy metabolism through a "one-to-many" projection pattern. While Crabp1 neurons are rapidly activated by cold exposure and physical activity, prolonged light exposure abrogates their firing and may mediate light-induced metabolic disorder. Together, we reveal a neural basis that integrate various physiological and environmental stimuli to control energy expenditure and body weight.

neuroscience↗

bioRxiv2025

Dynamic regulation of NeuroD1 expression level by a novel viral construct during astrocyte-to-neuron reprogramming

Astrocyte-to-neuron reprogramming presents a viable approach for regenerative medicine. The reprogramming factor NeuroD1 has demonstrated capability of neuronal reprogramming with high efficiency both in culture and in the injured central nervous system. High level of NeuroD1 expression is required to break down the cellular identity barrier for a successful reprogramming, and yet persistence of this high level drives the reprogrammed neurons primarily to glutamatergic subtype. This is consistent with the critical role of NeuroD1 in determination of glutamatergic neuronal lineage during development. However, diversified neuronal subtypes are needed to establish appropriate neuronal connectivity in disease/injury conditions. We reason that continuously high level of NeuroD1 expression forces the reprogrammed neurons into glutamatergic subtype, and that reducing NeuroD1 level after reprogramming may allow generation of neurons with diversified subtypes. For this purpose, we engineered a novel viral expression vector by which NeuroD1 expression can be dynamically regulated during the reprogramming process. Specifically, the target site of a neuron-specific microRNA (miR-124) is incorporated in the expression system. Therefore, this novel construct would still achieve a high NeuroD1 expression level in astrocytes for reprogramming to occur and yet reduce its level in the reprogrammed neurons by suppression of endogenous miR-124. In this study, we demonstrated that this construct elicits a dynamic gene expression pattern with much reduced level of NeuroD1 at later stages of neuronal reprogramming. We also showed that this construct still retains relatively high reprogramming efficiency and can generate mature neurons with an enhanced GABAergic neuronal phenotype.

neuroscience↗

bioRxiv2025

Detection of Diffuse to Focal Myocardial Fibrosis by Cardiovascular Magnetic Resonance Against Histology in Mini-Swine

BackgroundMyocardial fibrosis predicts adverse outcomes in myocardial infarction (MI) and other cardiovascular conditions. Cardiovascular magnetic resonance (CMR) can non-invasively detect focal and diffuse myocardial fibrosis, but comprehensive validation against histology remains scarce. AimsTo assess the comparative diagnostic performance of CMR methods in detecting myocardial fibrosis, using a mini-swine model and histology as gold standard. MethodsEighteen mini-swine (16 MI; 2 healthy) underwent CMR cine, LGE, T1- and ECV-mapping. Two commonly-used T1-mapping methods - MOLLI 5(3)3 and ShMOLLI 5(1)1(1)1 - were included. Pathological sections were categorized as infarcted, peri-infarct, remote and healthy myocardium based on triphenyl tetrazolium chloride staining. Fibrotic burden was quantified by collagen volume fraction (CVF) into severe (CVF[≥]30%), moderate (CVF=10-25%), and mild (CVF=3-14%). The relationships between LGE, T1, ECV and CVF, and diagnostic performance using area-under-the-curve (AUC), were analyzed. ResultsFor detecting severe fibrosis, LGE, T1 and ECV all had excellent diagnostic performance (AUC: LGE=0.93, ECVShMOLLI=0.96, T1ShMOLLI=0.91, T1MOLLI=0.93, ECVMOLLI=0.88). ECVShMOLLI showed significantly better discriminatory accuracy than ECVMOLLI in detecting severe fibrosis and MI (both p<0.05), with the highest correlation to CVF (ECVShMOLLI r=0.86, ECVMOLLI r=0.82, T1ShMOLLI r=0.77, T1MOLLI r=0.77, semi-quantitative LGE r=0.75). Only T1ShMOLLI and ECVShMOLLI, but not LGE or T1MOLLI/ECVMOLLI, differentiated remote myocardium with mild fibrosis (CVF=8.23%) from healthy myocardium (CVF=2.01%). ConclusionsCMR can detect severe to mild myocardial fibrosis as validated against histology. For low-grade fibrosis, T1-mapping significantly outperformed LGE. Choice of CMR methodologies matters for myocardial fibrosis detection, which has importance for clinical trial design.

pathology↗

bioRxiv2025

easyEWAS: a flexible and user-friendly R package for Epigenome-Wide Association Study

MotivationRapid advancements in high-throughput sequencing technologies especially the Illumina DNA methylation Beadchip greatly fueled the surge in epigenome-wide association study (EWAS), providing crucial insights into intrinsic DNA methylation modifications associated with environmental exposure, diseases, and health traits. However, current tools are complex and less user-friendly to accommodate appropriate EWAS designs and make downstream analyses and result interpretations complicated, especially for clinicians and public health professionals with limited bioinformatic skills. ResultsWe integrated the current state-of-the-art EWAS analysis methods and tools to develop a flexible and user-friendly R package easyEWAS for conducting DNA methylation-based research using Illumina DNA methylation Beadchips. With easyEWAS, we provide a battery of statistical methods to support differential methylation position analysis across various scenarios, as well as differential methylation region analysis based on the DMRcate method. To facilitate result interpretation, we provide comprehensive functional annotation and result visualization functionalities. Additionally, a bootstrap-based internal validation was incorporated into easyEWAS to ensure the robustness of EWAS results. Evaluation in asthma patients as the example demonstrated that easyEWAS could simplify and streamline the conduction of EWAS and corresponding downstream analyses, thus effectively advancing DNA methylation research in public health and clinical settings. Availability and implementationeasyEWAS is implemented as an R package and is available at https://github.com/ytwangZero/easyEWAS. Contactxu.gao@pku.edu.cn, ytwang@pku.edu.cn

bioinformatics↗

bioRxiv2024

Huntingtin interactome reveals huntingtin role in regulation of double strand break DNA damage response (DSB/DDR), chromatin remodeling and RNA processing pathways

Huntingtons Disease (HD), a progressive neurodegenerative disorder with no disease-modifying therapies, is caused by a CAG repeat expansion in the HD gene encoding polyglutamine-expanded huntingtin (HTT) protein. Mechanisms of HD cellular pathogenesis and cellular functions of the normal and mutant HTT proteins are still not completely understood. HTT protein has numerous interaction partners, and it likely provides a scaffold for assembly of multiprotein complexes many of which may be altered in HD. Previous studies have implicated DNA damage response in HD pathogenesis. Gene transcription and RNA processing has also emerged as molecular mechanisms associated with HD. Here we used multiple approaches to identify HTT interactors in the context of DNA damage stress. Our results indicate that HTT interacts with many proteins involved in the regulation of interconnected DNA repair/remodeling and RNA processing pathways. We present evidence for a role for HTT in double strand break repair mechanism. We demonstrate HTT functional interaction with a major DNA damage response kinase DNA-PKcs and association of both proteins with nuclear speckles. We show that S1181 phosphorylation of HTT is regulated by DSB, and can be carried out (at least in vitro) by DNA-PK. Furthermore, we show HTT interactions with RNA binding proteins associated with nuclear speckles, including two proteins encoded by genes at HD modifier loci, TCERG1 and MED15, and with chromatin remodeling complex BAF. These interactions of HTT may position it as an important scaffolding intermediary providing integrated regulation of gene expression and RNA processing in the context of DNA repair mechanisms.

neuroscience↗

bioRxiv2024

Comparison of imaging-based single-cell resolution spatial transcriptomics profiling platforms using formalin-fixed, paraffin-embedded tumor samples

Imaging-based spatial transcriptomics (ST) is evolving rapidly as a pivotal technology in studying the biology of tumors and their associated microenvironments. However, the strengths of the commercially available ST platforms in studying spatial biology have not been systematically evaluated using rigorously controlled experiments. In this study, we used serial 5-m sections of formalin-fixed, paraffin-embedded surgically resected lung adenocarcinoma and pleural mesothelioma tumor samples in tissue microarrays to compare the performance of the single cell ST platforms CosMx, MERFISH, and Xenium (uni/multi-modal) platforms in reference to bulk RNA sequencing, multiplex immunofluorescence, GeoMx Digital Spatial Profiler, and hematoxylin and eosin staining data for the same samples. In addition to objective assessment of automatic cell segmentation and phenotyping, we performed pixel-resolution manual evaluation of phenotyping to carry out pathologically meaningful comparison between ST platforms. Our study detailed the intricate differences between the ST platforms, revealed the importance of parameters such as tissue age and probe design in determining the data quality, and suggested reliable workflows for accurate spatial profiling and molecular discovery.

bioinformatics↗