Search bioRxiv⌕ Search

Biology subjects

Gupta, S.

Publications and source records attributed to Gupta, S..

At least 199 records · Page 11Linked to original sources

eMIND: Enabling automatic collection of protein variation impacts in Alzheimer's disease from the literature

Alzheimers disease and related dementias (AD/ADRDs) are among the most common forms of dementia, and yet no effective treatments have been developed. To gain insight into the disease mechanism, capturing the connection of genetic variations to their impacts, at the disease and molecular levels, is essential. The scientific literature continues to be a main source for reporting experimental information about the impact of variants. Thus, development of automatic methods to identify publications and extract the information from the unstructured text would facilitate collecting and organizing information for reuse. We developed eMIND, a deep learning-based text mining system that supports the automatic extraction of annotations of variants and their impacts in AD/ADRDs. In particular, we use this method to capture the impacts of protein-coding variants affecting a selected set of protein properties, such as protein activity/function, structure and post-translational modifications. We conducted an evaluation on the efficacy of eMIND to extract variant impact relations and obtained a recall of 0.84 and a precision of 0.94. The publications and extracted information are integrated into the UniProtKB computationally mapped bibliography to expand annotations on protein entries. eMINDs text-mined output are presented using controlled vocabularies and ontologies for variant, disease and impact along with the evidence sentences. A sample of annotated abstracts can be accessed at URL: https://research.bioinformatics.udel.edu/itextmine/emind.

bioinformatics↗

DNA hypomethylation promotes the expression of CASPASE-4 which exacerbates neuroinflammation and amyloid-β deposition in Alzheimer's disease

Alzheimers Disease (AD) is the 6th leading cause of death in the US. It is established that neuroinflammation contributes to the synaptic loss, neuronal death, and symptomatic decline of AD patients. Accumulating evidence suggests a critical role for microglia, innate immune phagocytes of the brain. For instance, microglia release pro-inflammatory products such as IL-1{beta} which is highly implicated in AD pathobiology. The mechanisms underlying the transition of microglia to proinflammatory promoters of AD remain largely unknown. To address this gap, we performed Reduced Representation Bisulfite Sequencing (RRBS) to profile global DNA methylation changes in human AD brains compared to no disease controls. We identified differential DNA methylation of CASPASE-4 (CASP4), which when expressed, can be involved in generation of IL-1{beta} and is predominantly expressed in immune cells. DNA upstream of the CASP4 transcription start site was hypomethylated in human AD brains, which was correlated with increased expression of CASP4. Furthermore, microglia from a mouse model of AD (5xFAD) express increased levels of CASP4 compared to wild-type (WT) mice. To study the role of CASP4 in AD, we developed a novel mouse model of AD lacking the mouse ortholog of CASP4, CASP11, which is encoded by mouse Caspase-4 (5xFAD/Casp4-/-). The expression of CASP11 was associated with increased accumulation of pathologic protein aggregate amyloid-{beta} (A{beta}) and increased microglial production of IL-1{beta} in 5xFAD mice. Utilizing RNA sequencing, we determined that CASP11 promotes unique transcriptomic phenotypes in 5xFAD mouse brains, including alterations of neuroinflammatory and chemokine signaling pathways. Notably, in vitro, CASP11 promoted generation of IL-1{beta} from macrophages in response to cytosolic A{beta} through cleavage of downstream effector Gasdermin D (G SDMD). We describe a role for CASP11 and GSDMD in the generation of IL-1{beta} in response to A{beta} and the progression of pathologic inflammation in AD. Overall, our results demonstrate that overexpression of CASP4 due to differential methylation in AD microglia contributes to the progression of AD pathobiology, thus identifying CASP4 as a potential target for immunotherapies for the treatment of AD.

neuroscience↗

Segment Anything for Microscopy

We present Segment Anything for Microscopy, a tool for interactive and automatic segmentation and tracking of objects in multi-dimensional microscopy data. Our method is based on Segment Anything, a vision foundation model for image segmentation. We extend it by training specialized models for microscopy data that significantly improve segmentation quality for a wide range of imaging conditions. We also implement annotation tools for interactive (volumetric) segmentation and tracking, that speed up data annotation significantly compared to established tools. Our work constitutes the first application of vision foundation models to microscopy, laying the groundwork for solving image analysis problems in these domains with a small set of powerful deep learning architectures.

bioinformatics↗

Chemokine receptor 5 signaling in PFC mediates stress susceptibility in female mice

Chronic stress induces changes in the periphery and the central nervous system (CNS) that contribute to neuropathology and behavioral abnormalities associated with psychiatric disorders. In this study, we examined the impact of peripheral and central inflammation during chronic social defeat stress (CSDS) in female mice. Compared to male mice, we found that female mice exhibited heightened peripheral inflammatory response and identified C-C motif chemokine ligand 5 (CCL5), as a stress-susceptibility marker in females. Blocking CCL5 signaling in the periphery promoted resilience to CSDS. In the brain, stress-susceptible mice displayed increased expression of C-C chemokine receptor 5 (CCR5), a receptor for CCL5, in microglia in the prefrontal cortex (PFC). This upregulation was associated with microglia morphological changes, their increased migration to the blood vessels, and enhanced phagocytosis of synaptic components and vascular material. These changes coincided with neurophysiological alterations and impaired blood-brain barrier (BBB) integrity. By blocking CCR5 signaling specifically in the PFC were able to prevent stress-induced physiological changes and rescue social avoidance behavior. Our findings are the first to demonstrate that stress-mediated dysregulation of the CCL5-CCR5 axis triggers excessive phagocytosis of synaptic materials and neurovascular components by microglia, resulting in disruptions in neurotransmission, reduced BBB integrity, and increased stress susceptibility. Our study provides new insights into the role of cortical microglia in female stress susceptibility and suggests that the CCL5-CCR5 axis may serve as a novel sex-specific therapeutic target for treating psychiatric disorders in females.

animal behavior and cognition↗

Hepatitis B virus x (HBx) protein increases cellular OCT3/4 and MYC and facilitates cellular reprogramming (of fibroblasts to iPSC)

HBx is a multifunctional protein coded by the Hepatitis B virus which is involved in various cellular processes such as proliferation, cell survival/apoptosis, and histone methylation. HBx was reported to be associated with liver cancer stem cells. The stemness inducing properties of HBx could also facilitate the generation of pluripotent stem cells from somatic cells. It is well established that somatic cells can be reprogrammed to induced pluripotent stem cells (iPSC) using a cocktail of transcription factors called Yamanakas factors (OCT4, SOX2, KLF4, and MYC). The reprogramming process proceeds step-by-step with reprogramming factor chromatin interactions, transcription and chromatin states changing during transitions. HBx is a broad spectrum trans-activator and therefore could facilitate these transitions. We electroporated low passage and high passage (difficult to reprogram) fibroblasts using Yamanakas factors (YF) with and without HBx and evaluated the reprogramming efficiency. We also investigated the tri-lineage and terminal differentiation potential of iPSC derived using HBx. We found, addition of HBx to YF, improves iPSC derivation, and increases the efficiency of iPSC generation from difficult or hard-to-reprogram samples such as high passage/senescent fibroblasts. Furthermore, we show that HBx can substitute the key transcription factor MYC in the YF cocktail to generate iPSC. Our results have practical value in improving the efficiency of pluripotent stem cell derivation from difficult to reprogram somatic cells in addition to providing some insights into the mechanisms of liver carcinogenesis in chronic hepatitis B. To conclude, HBx improves the reprogramming efficiency of YFs. HBx increases the cellular levels of OCT3/4 and MYC. Lay summaryHBx is a protein made by hepatitis B virus. Yamanakas Factors (YF) are a mixture of master-proteins which are used to convert adult cells to embryonic stem cells. We found that HBx protein can augment the efficiency of YF in generating these stem cells (concept summary figure).

cell biology↗

TNFR1/p38αMAPK signaling in Nex+ supraspinal neurons regulates sex-specific chronic neuropathic pain

Upregulation of soluble tumor necrosis factor (sTNF) cytokine signaling through TNF receptor 1 (TNFR1) and subsequent neuronal hyperexcitability are observed in both animal models and human chronic neuropathic pain (CNP) (Clark et al., 2013; Empl et al., 2001; Ji et al., 2018; Lindenlaub and Sommer, 2003). To test the hypothesis that supraspinal circuitry is critical to pain chronification, we studied the intersect between supraspinal TNFR1 mediated neuronal signaling and sex specificity by selectively removing TNFR1 in Nex+ neurons in adult mice (NexCreERT2::TNFR1f/f). We determined that following chronic constriction injury (CCI), pain resolves in males; however, female acute pain transitions to chronic. Subsequently, we investigated two downstream pathways, p38MAPK and NF-{kappa}B, important in TNFR1 signaling and injury response. We detected p38MAPK and NF-{kappa}B activation in male cortical tissue; however, p38MAPK phosphorylation was reduced in NexCreERT2::TNFR1f/f males. We observed similar behavioral results following CCI in NexCreERT2::p38MAPKf/f mice. Previously, we established estrogens ability to modulate sTNF/TNFR1 signaling in CNP, which may contribute to female prevalence of CNP (Bouhassira et al., 2008; Claiborne et al., 2006; de Mos et al., 2007; Del Rivero et al., 2019; Li et al., 2009). To explore the intersection between estrogen and inflammation in CNP we used a combination therapy of an estrogen receptor {beta} (ER {beta}) inhibitor with a sTNF/TNFR1 or general p38MAPK inhibitor. We determined both combination therapies lend "male-like" therapeutic relief to females following CCI. These data suggest that TNFR1/p38MAPK signaling in Nex+ neurons in CNP is male-specific and lack of therapeutic efficacy following sTNF inhibition in females is due to ER {beta} interference. These studies highlight sex-specific differences in pathways important to pain chronification and elucidate potential therapeutic strategies that would be effective in both sexes.

neuroscience↗

SCO-spondin knockout mice exhibit small brain ventricles and mild spine deformation

Reissners fiber (RF) is an extracellular polymer comprising the large monomeric protein SCO-spondin (SSPO) secreted by the subcommissural organ (SCO) that extends through cerebrospinal fluid (CSF)-filled ventricles into the central canal of the spinal cord. In zebrafish, RF and CSF-contacting neurons (CSF-cNs) form an axial sensory system that detects spinal curvature, instructs morphogenesis of the body axis, and enables proper alignment of the spine. In mammalian models, RF has been implicated in CSF circulation. However, challenges in manipulating Sspo, an exceptionally large gene of 15,719 nucleotides, with traditional approaches has limited progress. Here, we generated a Sspo knockout mouse model using CRISPR/Cas9-mediated genome-editing. Sspo knockout mice lacked RF-positive material in the SCO and fibrillar condensates in the brain ventricles. Remarkably, Sspo knockout brain ventricle sizes were reduced compared to littermate controls. Minor defects in thoracic spine curvature were detected in Sspo knockouts, which did not alter basic motor behaviors tested. Altogether, our work in mouse demonstrates that SSPO and RF regulate ventricle size during development but only moderately impact spine geometry.

neuroscience↗

Identification of Sequence Determinants for the ABHD14 Enzymes

Over the course of evolution, enzymes have developed remarkable functional diversity in catalyzing important chemical reactions across various organisms, and understanding how new enzyme functions might have evolved remains an important question in modern enzymology. To systematically annotate functions, based on protein sequences and available biochemical studies, enzymes with similar catalytic mechanisms and/or aspects of catalysis have been clustered together into an enzyme superfamily. Typically, enzymes within a superfamily have similar overall three-dimensional structures, conserved key catalytic residues, but large variations in substrate recognition sites and residues to accommodate the diverse biochemical reactions that are catalyzed within the superfamily. The serine hydrolases are an excellent example of such an enzyme superfamily, that based on known enzymatic activities and protein sequences, is split almost equally into the serine proteases and metabolic serine hydrolases. Within the metabolic serine hydrolases, are two outlying members, ABHD14A and ABHD14B, that have high sequence similarity, but their functions remained cryptic till recently. While ABHD14A still lacks any functional annotation to date, we recently showed that ABHD14B functions as a lysine deacetylase in mammals. Given their high sequence similarity, automated databases wrongly assign ABHD14A and ABHD14B as the same enzyme, and therefore, annotating functions to them in various organisms maybe problematic. In this paper, we present a bioinformatics study coupled to biochemical experiments, that identifies key sequence determinants for both ABHD14A and ABHD14B, and enables better classification for them. Additionally, we map these enzymes on an evolutionary timescale, and provide a resource in studying these interesting enzymes in different organisms.

biochemistry↗

Investigating the basis of lineage decisions and developmental trajectories in the dorsal spinal cord through pseudotime analyses

Dorsal interneurons (dIs) in the spinal cord encode the perception of touch, pain, heat, itch, and proprioception. While previous studies using genetic strategies in animal models have revealed important insights into dI development, the molecular details by which dIs arise as distinct populations of neurons remain incomplete. We have developed a resource to investigate dI fate specification by combining a single-cell RNA-Seq atlas of mouse ESC-derived dIs with pseudotime analyses. To validate this in silico resource as a useful tool, we used it to first identify novel genes that are candidates for directing the transition states that lead to distinct dI lineage trajectories, and then validated them using in situ hybridization analyses in the developing mouse spinal cord in vivo. We have also identified a novel endpoint of the dI5 lineage trajectory and found that dIs become more transcriptionally homogenous during terminal differentiation. Together, this study introduces a valuable tool for further discovery about the timing of gene expression during dI differentiation and demonstrates its utility clarifying dI lineage relationships. Summary statementPseudotime analyses of embryonic stem cell-derived dorsal spinal interneurons reveals both novel regulators and lineage relationships between different interneuron populations.

neuroscience↗

EPINEST, an agent-based model to simulate epidemic dynamics in large-scale poultry production and distribution networks

The rapid intensification of poultry production raises important concerns about the associated risks of zoonotic infections. Here, we introduce EPINEST (EPI-demic NEtwork Simulation in poultry Transportation systems): an agent-based modelling designed to simulate pathogen transmission within realistic poultry production and distribution networks. The modular structure of the model allows for easy parameterization to suit specific countries and system configurations. Moreover, the framework enables the replication of a wide range of eco-epidemiological scenarios by incorporating diverse pathogen life-history traits, modes of transmission and interactions between multiple strains and/or pathogens. EPINEST was developed in the context of an interdisciplinary multicentre study conducted in Bangladesh, India, Vietnam and Sri Lanka, and will facilitate the investigation of the spreading patterns of various health hazards such as avian influenza, Campylobacter, Salmonella and antimicrobial resistance in these countries. Furthermore, this modelling framework holds potential for broader application in veterinary epidemiology and One Health research, extending its relevance beyond poultry to encompass other livestock species and disease systems.

bioinformatics↗

Detection of viral infection in cell lines using ViralCellDetector

Cell lines are commonly used in research to study biology, including gene expression regulation, cancer progression, and drug responses. However, cross-contaminations with bacteria, mycoplasma, and viruses are common issues in cell line experiments. Detection of bacteria and mycoplasma infections in cell lines is relatively easy but identifying viral infections in cell lines is difficult. Currently, there are no established methods or tools available for detecting viral infections in cell lines. To address this challenge, we developed a tool called ViralCellDetector that detects viruses through mapping RNA-seq data to a library of virus genome. Using this tool, we observed that around 10% of experiments with the MCF7 cell line were likely infected with viruses. Furthermore, to facilitate the detection of samples with unknown sources of viral infection, we identified the differentially expressed genes involved in viral infection from two different cell lines and used these genes in a machine learning approach to classify infected samples based on the host response gene expression biomarkers. Our model reclassifies the infected and non-infected samples with an AUC of 0.91 and an accuracy of 0.93. Overall, our mapping- and marker-based approaches can detect viral infections in any cell line simply based on readily accessible RNA-seq data, allowing researchers to avoid the use of unintentionally infected cell lines in their studies.

bioinformatics↗

Arsenophonus symbiosis with louse flies: multiple origins, coevolutionary dynamics, and metabolic significance

Arsenophonus is a widespread insect symbiont with life strategies that vary from parasitism to obligate mutualism. In insects living exclusively on vertebrate blood, mutualistic Arsenophonus strains are presumed to provide B vitamins missing in the insect host diet. Hippoboscidae, obligate blood-feeders related to tsetse flies, were previously suggested to have acquired Arsenophonus symbionts in several independent events. Based on comparative genomic analyzes of eleven Hippoboscidae-associated strains, nine of them newly assembled, we reveal a wide range of their genomic characteristics and phylogenetic affiliations. Phylogenetic patterns and genomic traits split the strains into two different types. Seven strains display characteristics of obligate mutualists with significantly reduced genomes and long phylogenetic branches. The remaining four genomes cluster on short branches, and their genomes resemble those of free-living bacteria or facultative symbionts. Both phylogenetic positions and genomic traits indicate that evolutionary history of the Hippoboscidae-Arsenophonus associations is a mixture of short-term coevolutions with at least four independent origins. The comparative approach to a reconstruction of B vitamin pathways across the available Arsenophonus genomes produced two kinds of patterns. On one hand, it indicated the different importance of individual B vitamins in the host-symbiont interaction. While some (riboflavin, pantothenate, folate) seem to be synthesized by all Hippoboscidae-associated obligate symbionts, pathways for others (thiamine, nicotinamide, cobalamin) are mostly missing. On the other hand, the broad comparison produced patterns which can serve as bases for further assessments of the pathways completeness and functionality. ImportanceInsects that live exclusively on vertebrate blood utilize symbiotic bacteria as a source of essential compounds, e.g. B vitamins. In louse flies, the most frequent symbiont originated in genus Arsenophonus, known from a wide range of insects. Here, we analyze genomic traits, phylogenetic origins, and metabolic capacities of eleven Arsenophonus strains associated with louse flies. We show that in louse flies Arsenophonus established symbiosis in at least four independent events, reaching different stages of symbiogenesis. This allowed for comparative genomic analysis, including convergence of metabolic capacities. The significance of the results is two-fold. First, based on a comparison of independently originated Arsenophonus symbioses, it determines the importance of individual B vitamins for the insect host. This expands our theoretical insight into insect-bacteria symbiosis. The second outcome is of methodological significance. We show that the comparative approach reveals artifacts that would be difficult to identify based on a single-genome analysis.

evolutionary biology↗

Spatial and Temporal Analysis of SARS-CoV-2 Genome Evolutionary Patterns

The spread of SARS-CoV-2 virus accompanied by availability of abundant sequence data publicly, provides a window for determining the spatio-temporal patterns of viral evolution in response to vaccination. In this study, SARS-CoV-2 genome sequences were collected from seven countries in the period January 2020-December 2022. The sequences were classified into three phases, namely: pre-vaccination, post-vaccination, and recent period. Comparison was performed between these phases based on parameters like mutation rates, selection pressure (dN/dS ratio), and transition to transversion ratios (Ti/Tv). Similar comparisons were performed among SARS-CoV-2 variants. Statistical significance was tested using Graphpad unpaired t-test. The comparative analysis showed an increase in the percent genomic mutation rates post-vaccination and in recent periods across different countries from the pre-vaccination phase. The dN/dS ratios showed positive selection that increased after vaccination, and the Ti/Tv ratios decreased after vaccination. C[->]U and G[->]U were the most frequent transitions and transversions in all the countries. However, U[->]G was the most frequent transversion in recent period. The Omicron variant had the highest genomic mutation rates, while Delta showed the highest dN/dS ratio. Mutation rates were highest in NSP3, S, N and NSP12b before and increased further after vaccination. NSP4 showed the largest change in mutation rates after vaccination. N, ORF8, ORF3a and ORF10 were under highest positive selection before vaccination. They were overtaken by E, S and NSP1 in the after vaccination as well as recent sequences, with the largest change observed in NSP1. Protein-wise dN/dS ratio was also seen to vary across the different variants. ImportanceIrrespective of the different vaccine technologies used, geographical regions and host genetics, variations in the SARS-CoV-2 genome have maintained similar patterns worldwide. To the best of our knowledge, there exists no other large-scale study of the genomic and protein-wise mutation patterns during the time course of evolution in different countries. Analysing the SARS-CoV-2 evolution patterns in response to spatial, temporal, and biological signals is important for diagnostics, therapeutics, and pharmacovigilance of SARS-CoV-2.

bioinformatics↗

Dopamine functionalized, red carbon quantum dots for in vivo bioimaging, cancer therapeutics, and neuronal differentiation

One of the crucial requirements of quantum dots for biological applications is their surface modifications for very specific and enhanced biological recognition and uptake. Toward this, we present the green synthesis of bright, red-emitting carbon quantum dots derived from mango leaf extract (mQDs). These mQDs are conjugated electrostatically with dopamine to form mQDs-dopamine (mQDs: DOPA) bioconjugates. Bright red fluorescence of mQDs was used for bioimaging and uptake in multiple cell lines, tissues, and in vivo models like zebrafish. mQDs exhibited the highest uptake in brain tissue as compared to others. mQD:DOPA conjugate induced cellular toxicity only in cancer cells while showing increased uptake in epithelial cells and zebrafish. Additionally, the mQDs: DOPA promoted neuronal differentiation of SH-SY5Y cells to complete neurons. Both mQDs and mQDs: DOPA exhibited potential for higher collective cell migrations implicating their future potential as next-generation tools for advanced biological and biomedical applications. TOCmQDs were electrostatically conjugated with dopamine (DOPA) to form the mQDs: DOPA bioconjugate. mQDs are used to image cells, tissues, and zebrafish embryos. mQDs: DOPA kills cancer cells, differentiates neuronal cells, and increases the uptake of mQDs in zebrafish embryos. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=116 SRC="FIGDIR/small/545347v1_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@f521a4org.highwire.dtl.DTLVardef@173a8f0org.highwire.dtl.DTLVardef@585271org.highwire.dtl.DTLVardef@8c959d_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

How human-derived brain organoids are built differently from brain organoids derived of genetically-close relatives: A multi-scale hypothesis

How genes affect tissue scale organization remains a longstanding biological puzzle. As experimental efforts are underway to solve this puzzle via quantification of gene expression, chromatin organization, cellular structure, and tissue structure, computational modeling efforts remain far behind. To help accelerate the computational modeling efforts, we review two recent publications, the first on a cellular-based model for tissues and the second on a model of a cell nucleus that includes a lamina shell and chromatin. We then address how the two models can be combined to ultimately test multiscale hypotheses linking the chromatin scale and the tissue scale. To be concrete, we turn to an in vitro system for the brain known as a brain organoid. We provide a multiscale hypothesis to distinguish structural differences between brain organoids built from induced-pluripotent human stem cells and from induced-pluripotent gorilla and chimpanzee stem cells. Recent experiments discover that a cell fate transition from neuroepithelial cells to radial glial cells includes a new intermediate state that is delayed in human-derived brain organoids as compared to their genetically-close relatives, which significantly narrows and lengthens the cells on the apical side [1]. Additional experiments revealed that the protein ZEB2 plays a major role in the emergence of this new intermediate state with ZEB2 mRNA levels peaking at the onset of the emergence [1]. We postulate that the enhancement of ZEB2 expression driving this intermediate state is potentially due to chromatin reorganization. More precisely, there exists critical strain triggering the reorganization that is higher for human-derived stem cells, thereby resulting in a delay. Such a hypothesis can readily be tested experimentally within individual cells and within brain organoids as well as computationally to help work towards solving the gene-to-tissue organization puzzle.

developmental biology↗

Structural principles of peptide-centric Chimeric Antigen Receptor recognition guide therapeutic expansion

Peptide-Centric Chimeric Antigen Receptors (PC-CARs), which recognize oncoprotein epitopes displayed by human leukocyte antigens (HLAs) on the cell surface, offer a promising strategy for targeted cancer therapy1. We have previously developed a PC-CAR targeting a neuroblastoma- associated PHOX2B peptide, leading to robust tumor cell lysis restricted by two common HLA allotypes2. Here, we determine the 2.1 [A] structure of the PC-CAR:PHOX2B/HLA-A*24:02/{beta}2m complex, which reveals the basis for antigen-specific recognition through interactions with CAR complementarity-determining regions (CDRs). The PC-CAR adopts a diagonal docking mode, where interactions with both conserved and polymorphic HLA framework residues permit recognition of multiple HLA allotypes from the A9 serological cross-reactivity group, covering a combined American population frequency of up to 25.2%. Comprehensive characterization using biochemical binding assays, molecular dynamics simulations, and structural and functional analyses demonstrate that high-affinity PC-CAR recognition of cross-reactive pHLAs necessitates the presentation of a specific peptide backbone, where subtle structural adaptations of the peptide are critical for high-affinity complex formation and CAR-T cell killing. Our results provide a molecular blueprint for engineering CARs with optimal recognition of tumor-associated antigens in the context of different HLAs, while minimizing cross-reactivity with self-epitopes.

biochemistry↗

3D structural human interactome reveals proteome-wide perturbations by disease mutations

Human genome sequencing studies have identified numerous loci associated with complex diseases. However, translating human genetic and genomic findings to disease pathobiology and therapeutic discovery remains a major challenge at multiscale interactome network levels. Here, we present a deep-learning-based ensemble framework, termed PIONEER (Protein-protein InteractiOn iNtErfacE pRediction), that accurately predicts protein binding partner-specific interfaces for all known protein interactions in humans and seven other common model organisms, generating comprehensive structurally-informed protein interactomes. We demonstrate that PIONEER outperforms existing state-of-the-art methods. We further systematically validated PIONEER predictions experimentally through generating 2,395 mutations and testing their impact on 6,754 mutation-interaction pairs, confirming the high quality and validity of PIONEER predictions. We show that disease-associated mutations are enriched in PIONEER-predicted protein-protein interfaces after mapping mutations from [~]60,000 germline exomes and [~]36,000 somatic genomes. We identify 586 significant protein-protein interactions (PPIs) enriched with PIONEER-predicted interface somatic mutations (termed oncoPPIs) from pan-cancer analysis of [~]11,000 tumor whole-exomes across 33 cancer types. We show that PIONEER-predicted oncoPPIs are significantly associated with patient survival and drug responses from both cancer cell lines and patient-derived xenograft mouse models. We identify a landscape of PPI-perturbing tumor alleles upon ubiquitination by E3 ligases, and we experimentally validate the tumorigenic KEAP1-NRF2 interface mutation p.Thr80Lys in non-small cell lung cancer. We show that PIONEER-predicted PPI-perturbing alleles alter protein abundance and correlates with drug responses and patient survival in colon and uterine cancers as demonstrated by proteogenomic data from the National Cancer Institutes Clinical Proteomic Tumor Analysis Consortium. PIONEER, implemented as both a web server platform and a software package, identifies functional consequences of disease-associated alleles and offers a deep learning tool for precision medicine at multiscale interactome network levels.

bioinformatics↗

Tackling emerging artemisinin resistance by modulating the defensive oxido-reductive mechanism of human malaria parasite by repurposing nitrofurantoin

Oxidative stress mediated cell death has remained the prime parasiticidal mechanism of front line anti-malarial, artemisinin (ART). The emergence of resistant Plasmodium parasites characterized by oxidative stress management due to impaired activation of ART as well as enhanced ROS detoxification has decreased its clinical efficacy. This gap can be filled by development of alternative chemotherapeutic agents to combat resistance defense mechanism. Interestingly, repositioning of clinically approved drugs presents an emerging approach for expediting anti-malarial drug development and resistance management. Herein, we evaluated the anti-malarial potential of Nitrofurantoin (NTF), a clinically used antibacterial drug, against intra-erythrocytic stages of ART-sensitive (Pf3D7) and resistant (PfKelch13R539T) strains of Plasmodium falciparum (Pf), alone and in combination with ART. NTF exhibited growth inhibitory effect at sub micro molar concentration by arresting parasite growth at trophozoite stage. It also inhibited the survival of resistant parasites as revealed by ring survival assay. Concomitantly, in vitro combination assay revealed synergistic association of NTF with ART. NTF was found to enhance the reactive oxygen and nitrogen species as well as induced mitochondrial membrane depolarization in parasite. Furthermore, we found that exposure of parasites to NTF disrupted their redox balance by impeding Pf Glutathione Reductase activity, which manifests in enhanced oxidative stress, inducing parasite death. In vivo administration of NTF, alone and in combination with ART in P. berghei ANKA infected mice blocked parasite multiplication and enhanced mean survival time. Overall, our results indicate NTF as a promising repurposable drug with therapeutic potential against drug sensitive as well as resistant parasites.

pharmacology and toxicology↗