bioRxiv Science⌕ Search

Biology subjects

Kang, M.

Publications and source records attributed to Kang, M..

At least 55 records · Page 3Linked to original sources

Interpretable Kolmogorov-Arnold Networks for Enzyme Commission Number Prediction

Accurate prediction of enzyme commission (EC) numbers remains a significant challenge in bioinformatics, limiting our ability to fully understand enzyme functions and their roles in biological processes. This paper presents the integration and evaluation of the next paradigm of deep learning architecture, named Kolmogorov-Arnold network (KAN), in state-of-the-art models for predicting EC numbers. KAN modules are incorporated into current state-of-the-art models to assess their impact on predictive performance. Additionally, we introduce a novel interpretation method, specifically designed for KANs, to identify relevant input features for a given prediction, addressing a current limitation in KANs. Our evaluation demonstrates that the integration of KANs significantly enhances predictive performance compared to the state-of-the-art deep learning models, with up to a 4.35% increase in micro-averaged F1 score and a 4.1% increase in macro-averaged F1 score. Moreover, our novel interpretation method not only enhances the predictions trustworthiness but also facilitates the discovery of motif sites within enzyme sequences. This innovative approach provides deeper insights into enzyme functionality and highlights potential new targets for research. The results underscore KANs effectiveness in improving enzymatic classification and advancing our understanding of enzyme structures and functions. The open-source code is publicly available at: https://github.com/datax-lab/kan_ecnumber.

bioinformatics↗

The 1001G+ project: A curated collection of Arabidopsis thaliana long-read genome assemblies to advance plant research

Arabidopsis thaliana was the first plant for which a high-quality genome sequence became available. The publication of the first reference genome sequence almost 25 years ago was already accompanied by genome-wide data on sequence polymorphisms in another accession, or naturally occurring strain. Since then, inventories of genome-wide diversity have been generated at increasingly precise levels. High-density genotype data for A. thaliana, including those from the 1001 Genomes Project, were key to demonstrating the enormous power of GWAS in inbred populations of wild plants, and the comparison of intraspecific polymorphism with interspecific divergence has illuminated many aspects of plant genome evolution. Over the past decade, an increasing number of nearly complete genome sequences have been published for many more accessions. Here, we highlight the diversity of a curated collection of previously published and so far unpublished genome sequences assembled using different types of long reads, including PacBio Continuous Long Reads (CLR), PacBio High Fidelity (HiFi) reads, and Oxford Nanopore Technologies (ONT) reads. This 1001 Genomes Plus (1001G+) resource is being made available at http://1001genomes.org. We invite colleagues with yet unpublished genome assemblies from A. thaliana accessions to contribute to this effort.

genomics↗

SCAD Delivery Platform: A Novel Approach for Efficient CNS and Extrahepatic Oligonucleotide Therapeutics

Oligonucleotide therapeutics, including antisense oligonucleotides (ASOs) and duplex RNAs like siRNA, saRNA, and miRNA, hold immense potential for treating genetic and acquired diseases by modulating gene expression in a target-specific manner. However, effective delivery to extrahepatic tissues, particularly the central nervous system (CNS), remains a significant challenge. While GalNAc conjugation has enabled liver-specific delivery, leading to several approved siRNA drugs for hepatic targets, CNS delivery lags. ASOs, on the other hand, can self-deliver to the CNS when administered locally, as seen with nusinersen and tofersen. To address this disparity, weve developed the Smart Chemistry Aided Delivery (SCAD) platform which enables duplex RNA delivery by conjugating it to an accessory oligonucleotide (ACO), which acts as an aptamer to mediate protein binding and facilitate cellular uptake. Through extensive screening, we identified an optimal SCAD architecture that demonstrates enhanced cell-free protein binding and in vitro activity. In rodent models, local administration of SCAD-siRNA conjugates resulted in broad biodistribution throughout the CNS and sustained mRNA knockdown for over five months, with a favorable safety profile. The SCAD platform also exhibited efficient delivery to other tissues, including the eye, the lung and the joint. These features support its potential for broader clinical applications, as evidenced by an ongoing trial targeting amyotrophic lateral sclerosis (ALS) associated with mutations in the SOD1 gene. The modular design of SCAD allows it to easily adapt to any duplex RNA, making it a powerful tool for advancing oligonucleotide therapeutics.

neuroscience↗

Hard-wired visual filters for environment-agnostic object recognition

Conventional deep neural networks (DNNs) are highly susceptible to variations in input domains, unlike biological brains which effectively adapt to environmental changes. Here, we demonstrate that hard-wired Gabor filters, replicating the structure of receptive fields in the brains early visual pathway, facilitate environment-agnostic object recognition without overfitting. Our approach involved fixing the pre-designed Gabor filters in the early layers of DNNs, preventing any alterations during training. Despite the restricted learning flexibility of this model, our networks maintained robust performance even under significant domain shifts, in contrast to conventional DNNs that typically fail in similar conditions. We found that our model effectively clustered identical "classes" across diverse domains, while conventional DNNs tend to cluster images by "domain" in the latent space. We observed that the fixed Gabor filters enabled networks to encode global shape information rather than local texture features, thereby mitigating the risk of overfitting. One sentence summaryHard-wired Gabor filters enable environment-agnostic object recognition without overfitting. Research HighlightsO_LIConventional deep neural networks (DNNs) are vulnerable to input domain variations C_LIO_LIHard-wired Gabor filters facilitate environment-agnostic object recognition C_LIO_LIFixed Gabor filters prevent overfitting and facilitate shape-based classifications C_LIO_LIOur model cluster identical "classes" while conventional DNNs cluster by "domain" C_LI

neuroscience↗

EMT Induction In Normal Breast Epithelial Cells By COX2-Expressing Fibroblasts

BackgroundThe tumor microenvironment (TME) plays a pivotal role in cancer progression, with cancer-associated fibroblasts (CAFs) significantly influencing tumor behavior. Especially, elevated COX2 expressing fibroblasts within the TME, notably in collagen-dense tumors like breast cancer, has been recently emphasized in the literature. However, the specific effect of COX2-expressing CAFs (COX2+ CAFs) on neighboring cells and their consequent role in cancer progression is not fully elucidated. MethodsWe induced COX2+ fibroblasts by forcing the fibroblasts forming aggregates to undergo Nemosis as a proxy for COX2+ CAFs. This approach enabled us to simulate the paracrine interactions between COX2+ CAFs and normal breast epithelial cells via conditioned media from COX2+ fibroblasts. We developed an innovative in vitro platform that combines cell mechanics-based analysis and biomolecular assays to study the interactions between COX2+ fibroblasts and normal breast epithelial cells. By focusing on the mechanical characteristics of the cells and the EMT marker expressions, we aimed to elucidate the paracrine mechanisms through which COX2+ CAFs influence the tumor microenvironment. ResultsOur in vitro findings reveal that COX2+ fibroblasts, through conditioned media, induce significant changes in the mechanical behavior of normal breast epithelial cells, facilitating their transition towards mesenchymal types. This transition was corroborated by increased expression of mesenchymal markers. By drawing parallels between COX2+ fibroblasts and COX2+ CAFs, we established a positive feedback loop involving COX2+ CAFs, prostaglandin E2 (PGE2), and the EP4-SNAI1 axes. ConclusionThis study advances our understanding of the potential mechanisms by which COX2+ CAFs influence tumor progression within the breast tumor microenvironment (TME) through controlled in vitro investigations. By integrating cell mechanics-based analysis, biomolecular assays, and innovative in vitro cell-based modeling of COX2+ CAFs, we have delineated the contributory role of these cells in a controlled setting. These insights lay a groundwork for future studies that could explore the implications of these findings in vivo, potentially guiding targeted therapeutic strategies.

cell biology↗

Machine Learning Driven Optimization for High Precision Cellular Droplet Bioprinting

Controlled volume microliter cell-laden droplet bioprinting is important for precise biologics deposition, reliably replicating 3D microtissue environments for building cell aggregates or organoids. To achieve this, we propose an innovative machine-learning approach to predict cell-laden droplet volumes according to input parameters. We developed a novel bioprinting platform capable of collecting high-throughput droplet images and generating an extensive dataset for training machine learning and deep learning algorithms. Our research compared the performance of three machine learning and two deep learning algorithms that predict droplet volume based on numerous bioprinting parameters. By adjusting bioink viscosity, nozzle size, printing time, printing pressure, and cell concentration as input parameters, we precisely could control droplet sizes, ranging from 0.1 {micro}L to 50 {micro}L in volume. We utilized a hydrogel precursor composed of 5% gelatin methacrylate and a mixture of 0.5% and 1% alginate, respectively. Additionally, we optimized the cell bioprinting process using green fluorescent protein-tagged 3T3 fibroblast cells. These models demonstrated superior predictive accuracy and revealed the interrelationships among parameters while taking minimal time for training and testing. This method promises to advance the mass production of organoids and microtissues with precise volume control for various biomedical applications.

bioengineering↗

Localized in vivo prodrug activation using radionuclides

Radionuclides used for imaging and therapy can show high molecular specificity in the body with appropriate targeting ligands. We hypothesized that local energy delivered by molecularly targeted radionuclides could chemically activate prodrugs at disease sites while avoiding activation in off-target sites of toxicity. As proof-of-principle, we tested whether this strategy of "RAdionuclide induced Drug Engagement for Release" (RAiDER) could locally deliver combined radiation and chemotherapy to maximize tumor cytotoxicity while minimizing exposure to activated chemotherapy in off-target sites. MethodsWe screened the ability of radionuclides to chemically activate a model radiation-activated prodrug consisting of the microtubule destabilizing monomethyl auristatin E caged by a radiation-responsive phenyl azide ("caged-MMAE") and interpreted experimental results using the radiobiology computational simulation suite TOPAS-nBio. RAiDER was evaluated in syngeneic mouse models of cancer using fibroblast activation protein inhibitor (FAPI) agents 99mTc-FAPI-34 and 177Lu-FAPI-04, the prostate-specific membrane antigen (PSMA) agent 177Lu-PSMA-617, combined with caged-MMAE or caged-exatecan. Biodistribution in mice, combined with clinical dosimetry, estimated the relationship between radiopharmaceutical uptake in patients and anticipated concentrations of activated prodrug using RAiDER. ResultsRAiDER efficiency varied by 250-fold across radionuclides (99mTc>177Lu>64Cu>68Ga>223Ra>18F), yielding up to 1.22{micro}M prodrug activation per Gy of exposure from 99mTc. Computational simulations implicated low-energy electron-mediated free radical formation as driving prodrug activation. Clinically relevant radionuclide concentrations chemically activated caged-MMAE restored its ability to destabilize microtubules and increased its cytotoxicity by up to 600-fold compared to non-irradiated prodrug. Mice treated with 99mTc-FAPI-34 and caged-MMAE accumulated up to 3000x greater concentrations of activated MMAE in tumors compared to other tissues. RAiDER with 99mTc-FAPI-34 or 177Lu-FAPI-04 delayed tumor growth, while monotherapies did not (P<0.03). Clinically-guided dosimetry suggests sufficient radiation doses can be delivered to activate therapeutically meaningful levels of prodrug. ConclusionThis proof-of-concept study shows that RAiDER is compatible with multiple radionuclides commonly used in nuclear medicine and has the potential to improve the efficacy of radiopharmaceutical therapies to treat cancer safely. RAiDER thus shows promise as an effective strategy to treat disseminated malignancies and broadens the capability of radiopharmaceuticals to trigger diverse biological and therapeutic responses. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=136 SRC="FIGDIR/small/606075v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@18aef37org.highwire.dtl.DTLVardef@5f36eforg.highwire.dtl.DTLVardef@10fa0ccorg.highwire.dtl.DTLVardef@105c416_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

Gut Microbiome Perturbation Affected Conjugative Transfer of Antimicrobial Resistance Genes

The global spread of antimicrobial resistance genes (ARGs) poses a significant threat to public health. While antibiotics effectively treat bacterial infections, they can also induce gut dysbiosis, the severity of which varies depending on the specific antibiotic treatment used. However, it remains unclear how gut dysbiosis affects the mobility and dynamics of ARGs. To address this, mice were pre-treated with streptomycin, ampicillin, or sulfamethazine, and then orally inoculated with Salmonella enterica serovar Typhimurium and S. Heidelberg carrying a multi-drug resistance IncA/C plasmid. The streptomycin pre- treatment caused severe microbiome perturbation, promoting high-density colonization of S. Heidelberg and S. Typhimurium, and enabling IncA/C transfer from S. Heidelberg to S. Typhimurium and a commensal Escherichia coli. The ampicillin pre-treatment induced moderate microbiome perturbation, supporting only S. Heidelberg colonization and IncA/C transfer to commensal E. coli. The sulfamethazine pre-treatment led to mild microbiome perturbation, favoring neither Salmonella spp. colonization nor conjugative plasmid transfer. The degree of gut dysbiosis also influenced the enrichment or depletion of ARGs associated with mobile plasmids or core commensal bacteria, respectively. These findings underscore the significance of pre-existing gut dysbiosis induced by various antibiotic treatments on ARG dissemination and may inform prudent antibiotic use practices.

microbiology↗

TOMM40 regulates hepatocellular and plasma lipid metabolism via an LXR-dependent pathway

The gene encoding TOMM40 (Transporter of Outer Mitochondrial Membrane 40) is adjacent to that encoding APOE, which has a central role in lipid and lipoprotein metabolism. Human genetic variants near APOE and TOMM40 are strongly associated with plasma lipid levels, but a specific role for TOMM40 in lipid metabolism has not been established. Investigating this, we show that suppression of TOMM40 in human hepatoma cells upregulates expression of APOE and LDLR in part via activation of LXRB (NR1H2) by oxysterols, with consequent increased uptake of VLDL and LDL. This is in part due to disruption of mitochondria-endoplasmic reticulum contact sites, with resulting accrual of reactive oxygen species and non-enzymatically derived oxysterols. With TOMM40 knockdown, cellular triglyceride and lipid droplet content are increased, effects attributable in part to receptor-mediated VLDL uptake, since lipid staining is significantly reduced by concomitant suppression of either LDLR or APOE. In contrast, cellular cholesterol content is reduced due to LXRB-mediated upregulation of the ABCA1 transporter as well as increased production and secretion of oxysterol-derived cholic acid. Consistent with the findings in hepatoma cells, in vivo knockdown of TOMM40 in mice results in significant reductions of plasma triglyceride and cholesterol concentrations, reduced hepatic cholesterol and increased triglyceride content, and accumulation of lipid droplets leading to development of steatosis. These findings demonstrate a role for TOMM40 in regulating hepatic lipid and plasma lipoprotein levels and identify mechanisms linking mitochondrial function with lipid metabolism. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=132 SRC="FIGDIR/small/600910v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@17b0c8forg.highwire.dtl.DTLVardef@17599aaorg.highwire.dtl.DTLVardef@1bb6ab2org.highwire.dtl.DTLVardef@15a035f_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

CLCC1 promotes hepatic neutral lipid flux and nuclear pore complex assembly

Imbalances in lipid storage and secretion lead to the accumulation of hepatocyte lipid droplets (LDs) (i.e., hepatic steatosis). Our understanding of the mechanisms that govern the channeling of hepatocyte neutral lipids towards cytosolic LDs or secreted lipoproteins remains incomplete. Here, we performed a series of CRISPR-Cas9 screens under different metabolic states to uncover mechanisms of hepatic neutral lipid flux. Clustering of chemical-genetic interactions identified CLIC-like chloride channel 1 (CLCC1) as a critical regulator of neutral lipid storage and secretion. Loss of CLCC1 resulted in the buildup of large LDs in hepatoma cells and knockout in mice caused liver steatosis. Remarkably, the LDs are in the lumen of the ER and exhibit properties of lipoproteins, indicating a profound shift in neutral lipid flux. Finally, remote homology searches identified a domain in CLCC1 that is homologous to yeast Brl1p and Brr6p, factors that promote the fusion of the inner and outer nuclear envelopes during nuclear pore complex assembly. Loss of CLCC1 lead to extensive nuclear membrane herniations, consistent with impaired nuclear pore complex assembly. Thus, we identify CLCC1 as the human Brl1p/Brr6p homolog and propose that CLCC1-mediated membrane remodeling promotes hepatic neutral lipid flux and nuclear pore complex assembly.

cell biology↗

Loss of p21-activated kinase 4 (PAK4) suppresses pancreatic tumor progression and metastasis through regulating E-cadherin

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a poor prognosis with early and frequent metastasis. While p21-activated kinase 4 (PAK4) has been implicated in cell migration, and invasion, the molecular mechanisms in PDAC remain unknown. In this study, we found that PAK4 overexpression was correlated with poor survival in PDAC patients through analysis of TCGA data. PAK4-amplified PDAC cells showed enhanced mobility in contrast with wild-type. PAK4 knockdown in PAK4 amplified cells inhibited cell migration, invasion, and displacement by increased and stabilized E-cadherin, which was attributed to decreased activity of Cdc42. PAK4 knock-in in PAK4 wild-type models enhanced cell migration, invasion, and displacement by reduced E-cadherin through elevated Cdc42 activity. PAK4 bounded to E-cadherin, Cdc42, and p120ctn in immunoprecipitation. In confocal imaging, the colocalization of PAK4, E-cadherin, p120ctn, and Cdc42 was also identified. In an orthotopic PDAC mouse model, PAK4 knockdown decreased primary tumor size and occurrence of malignant ascites by activation of E-cadherin. Notably, in patients tissue specimens, inverse correlation on expression of PAK4 and E-cadherin were also shown. In conclusion, our study highlights that PAK4 promotes invasive and metastatic behavior by regulating E-cadherin in PDAC. PAK4 could be a potential therapeutic target for PDAC patients. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=120 SRC="FIGDIR/small/594599v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@1755a23org.highwire.dtl.DTLVardef@170b2a1org.highwire.dtl.DTLVardef@1df96edorg.highwire.dtl.DTLVardef@2dc46b_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

Quantitative single cell mass spectrometry reveals the dynamics of plant natural product biosynthesis

Plants produce an extraordinary array of complex natural products (specialized metabolites). Since the biosynthetic genes that are responsible for synthesis of these molecules are often localized to rare or distinct cell types, recently developed single cell RNA-sequencing (scRNA-seq) approaches have tremendous potential to resolve these complex pathways. In contrast, detection, identification, and quantification of metabolites in single cells has remained challenging. Here, we report a robust method for single cell mass spectrometry in which we rigorously characterize and quantify the concentrations of four classes of natural products in individual cells of leaf, root, and petal of the medicinal plant Catharanthus roseus. These single cell mass spectrometry datasets reveal information about the biosynthetic processes that cannot be determined from the corresponding scRNA-seq data alone, providing a highly resolved picture of natural product biosynthesis at cell-specific resolution.

biochemistry↗

Cardiaca adipokinetic hormone and hedgehog signaling combine to generate intracellular waves of Ca++ in starved Drosophila melanogaster fat body

The Drosophila melanogaster fat body combines the functions of the vertebrate liver and fat. It plays a central role in metabolism where it integrates information about nutritional status to regulate fat utilization. During feeding, signaling through the Insulin Receptor causes lipogenesis, while fasting leads to signaling through the cardiaca Adipokinetic Hormone Receptor (AKHR) and mobilization of lipid stores. Here we examine intracellular calcium levels in the fat body during fasting. In fasting early third instar larvae, spikes of intracellular calcium are generated in the fat body lobes on either side of the brain. These spikes propagate through a narrow connection into the main lobes of the fat body that lie along the length of the larva. The spikes of intracellular Ca++ are dependent on the corpora cardiaca AKH expressing neurons and AKHR. Unexpectedly, the spikes also require Hedgehog (Hh) signaling from the midgut enterocytes and within the fat body. When Hh signaling is blocked, the Ca++ levels in the fat body are elevated and the spiking behavior lost. Hh signaling appears to regulate fat body intracellular Ca++ using both the transcription factor Cubitus interruptus and the trimeric G protein Gi. AKH/Hh signaling in the fat body lobes on either side of the brain appears to function as a pulse generator to initiate Ca++ spikes that then propagate through the main lobes of the fat body. These studies show how signaling from the brain and the midgut and within the fat body are integrated to regulate a key intracellular second messenger.

physiology↗

Mapping single-cell developmental potential in health and disease with interpretable deep learning

Single-cell RNA sequencing (scRNA-seq) has transformed our understanding of cell fate in developmental systems. However, identifying the molecular hallmarks of potency - the capacity of a cell to differentiate into other cell types - has remained challenging. Here, we introduce CytoTRACE 2, an interpretable deep learning framework for characterizing potency and differentiation states on an absolute scale from scRNA-seq data. Across 31 human and mouse scRNA-seq datasets encompassing 28 tissue types, CytoTRACE 2 outperformed existing methods for recovering experimentally determined potency levels and differentiation states covering the entire range of cellular ontogeny. Moreover, it reconstructed the temporal hierarchy of mouse embryogenesis across 62 timepoints; identified pan-tissue expression programs that discriminate major potency levels; and facilitated discovery of cellular phenotypes in cancer linked to survival and immunotherapy resistance. Our results illuminate a fundamental feature of cell biology and provide a broadly applicable platform for delineating single-cell differentiation landscapes in health and disease.

genomics↗

AI-driven Classification of Cancer-Associated Fibroblasts Using Morphodynamic and Motile Features

The heterogeneous natures of cancer-associated fibroblasts (CAFs) play critical roles in cancer progression, with some promoting tumor growth while others inhibit it. To utilize CAFs as a target for cancer treatment, issues with subtypes of CAFs must be resolved such that specific pro-tumorigenic subtypes can be suppressed or reprogrammed into anti-tumorigenic ones. Currently, single-cell RNA sequencing (scRNA-Seq) is a prevalent strategy for classifying CAFs, primarily based on their biomolecular features. Alternatively, this study proposes assessing CAFs on a larger biophysical scale, focusing on cell morphological and motile features. Since these features are downstream effectors of differential gene expression combinations, they can serve as holistic descriptors for CAFs, offering a complementary strategy for classifying CAF subtypes. Here, we propose an artificial intelligence (AI) classification framework to comprehensively characterize CAF subtypes using morphodynamic and motile features. This framework extracts these features from label-free live-cell imaging data of CAFs employing advanced deep learning and machine learning algorithms. The results of this study highlight the ability of morphodynamic and motile features to complement biomolecular features in accurately reflecting CAF subtype characteristics. In essence, our AI-based classification framework not only provides valuable insights into CAF biology but also introduces a novel approach for comprehensively describing and targeting heterogeneous CAF subtypes based on biophysical features.

cancer biology↗

An RXLR effector targets ER-Golgi interface to induce ER stress and necrotic cell death

To achieve successful colonization, the pathogen secretes hundreds of effectors into host cells to manipulate the hosts immune response. Despite numerous studies, the molecular mechanisms underlying effector-induced necrotic cell death remain elusive. In this study, we identified a novel virulent RXLR effector named Pc12 from P. capsici. Pc12 induces necrosis by triggering a distinct ER stress response through its interaction with Rab13-2. Unlike conventional hypersensitive response cell death associated with effector-triggered immunity, Pc12-induced cell death does not coincide with defense gene expression. Instead, it induces the aggregation of ER-resident proteins and confines secretory proteins within the ER. Pc12 interacts with Rab13-2, exhibiting a specific affinity for the active form of Rab13-2. Thus, the complex of Pc12 and Rab13-2 mimics the conformation of the inactive state of Rab13-2, subsequently recruiting the Rab-escort protein (REP). This process results in disruptions in vesicle formation within the ER-Golgi trafficking pathway. Furthermore, the substitution of a single amino acid of Rab13-2 structurally predicted to be crucial for the Pc12 interaction decreased the interaction with Pc12 while maintaining the interaction with REP1. These findings offer valuable insights into the ER stress-mediated cell death as well as a potential strategy for enhancing resistance against pathogens.

plant biology↗

A distinctive evolution of alveolar T cell responses is associated with clinical outcomes in unvaccinated patients with SARS-CoV-2 pneumonia

Pathogen clearance and resolution of inflammation in patients with pneumonia require an effective local T cell response. Nevertheless, local T cell activation may drive lung injury, particularly during prolonged episodes of respiratory failure characteristic of severe SARS-CoV-2 pneumonia. While T cell responses in the peripheral blood are well described, the evolution of T cell phenotypes and molecular signatures in the distal lung of patients with severe pneumonia caused by SARS-CoV-2 or other pathogens is understudied. Accordingly, we serially obtained 432 bronchoalveolar lavage fluid samples from 273 patients with severe pneumonia and respiratory failure, including 74 unvaccinated patients with COVID-19, and performed flow cytometry, transcriptional, and T cell receptor profiling on sorted CD8+ and CD4+ T cell subsets. In patients with COVID-19 but not pneumonia secondary to other pathogens, we found that early and persistent enrichment in CD8+ and CD4+ T cell subsets correlated with survival to hospital discharge. Activation of interferon signaling pathways early after intubation for COVID-19 was associated with favorable outcomes, while activation of NF-{kappa}B-driven programs late in disease was associated with poor outcomes. Patients with SARS-CoV-2 pneumonia whose alveolar T cells preferentially targeted the Spike and Nucleocapsid proteins tended to experience more favorable outcomes than patients whose T cells predominantly targeted the ORF1ab polyprotein complex. These results suggest that in patients with severe SARS-CoV-2 pneumonia, alveolar T cell interferon responses targeting structural SARS-CoV-2 proteins characterize patients who recover, yet these responses progress to NF-{kappa}B activation against non-structural proteins in patients who go on to experience poor clinical outcomes.

systems biology↗

RAG-17: A Novel siRNA Conjugate Demonstrating Efficacy in Late-Stage Treatment of SOD1G93A ALS mice

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by rapid progression and high mortality. With genetic mutations, particularly in the SOD1 gene, playing a significant role in ALS pathogenesis, targeted therapies have become a primary focus. This study introduces RD-12500 (RAG-17), a novel siRNA-ACO (Accessory Oligonucleotide) conjugate designed to address the challenges of delivering duplex RNAs to the central nervous system (CNS). RD-12500 exhibits remarkable in vitro stability and target specificity with minimal immunostimulation. In vivo studies demonstrate its extensive CNS biodistribution, sustained accumulation post-intrathecal administration, and a robust dose-exposure-activity correlation. Notably, RD-12500 significantly reduces cerebrospinal fluid (CSF) SOD1 protein levels, indicating potent SOD1 mRNA and protein knockdown in cynomolgus monkeys. Most notably, our study breaks new ground by demonstrating the effectiveness of RD-12500 in late-stage treatment scenarios. In SOD1G93A ALS mice, post-onset administration of RD-12500 significantly delayed disease progression, improved motor function, and extended survival, marking a significant advancement over other treatments which are typically initiated pre-symptomatically in the same model mice. These findings suggest RD-12500s potential to provide therapeutic benefits not only to pre-symptomatic but also to post-symptomatic and late-stage SOD1-ALS patients.

pharmacology and toxicology↗